1 Cross-Cultural Management

2 Chapter 1 Meanings and Dimensions of CultureOutline Chap1-1 Cross-cultural management Chap1-2 Globalization Chap1-3 Definitions of culture Chap1-4 Nature of culture Chap1-5 Cultural values Chap1-6 Dimensions of culture Chap1-7 Attitudinal Dimensions of Culture Chap1-8 Trompenaars’ s Cultural Dimensions

3 Chap1-1 Cross-cultural management

4 What is Cross-Cultural Management?CCM is a fairly new field that is based on theories and research from: Cross Cultural Psychology International Business Organizational Behaviour Human Resources Anthropology

5 Goals for Cross-Cultural ManagementCross Cultural Management seeks to understand how national cultures affect management practices identify the similarities and differences across cultures in various management practices and organizational contexts increase effectiveness in global management

6 Chap1-2 Globalization

7 Globalization Like it or not, globalization is here…to stay.Most large companies have some kind of business relations with customers, companies, employees or various stake-holders in other countries…and cultures. (Global corporations) Many employees and managers deal with people from other cultures on a constant basis Most of us have a close experience with only one or two cultures…=>

8 Globalization We do not understand people from other cultures as readily and intuitively as people from our own culture => Cross cultural management helps organization members to gain better understanding of other cultures, of their culture and of the consequences of people from different cultures working together

9 Chap1-3 Definitions of culture

10 Culture Definition: acquired knowledge that people use to interpret experience and generate social behavior. Culture forms values, creates attitude, influences behavior.

11 Chap1-4 Nature of culture

12 Culture Characteristics of culture include: Learned SharedTransgenerational Symbolic Patterned Adaptive

13 Cultural diversity (P4: Culture and types of handshake)Cultural values (P5: Priorities of cultural values: US, Japan) (P5: examples where culture can affect management approaches) Depict cultural diversity through concentric circles.

14 Chap1-5 Cultural values

15 Priorities of Cultural ValuesUnited States 1. Freedom 2. Independence 3. Self-reliance 4. Equality 5. Individualism 6. Competition 7. Efficiency 8. Time 9. Directness 10. Openness Japan 1. Belonging 2. Group harmony 3. Collectiveness 4. Age/seniority 5. Group consensus 6. Cooperation 7. Quality 8. Patience 9. Indirectness 10. Go-between Arab Countries 1. Family security 2. Family harmony 3. Parental guidance 4. Age 5. Authority 6. Compromise 7. Devotion 8. Patience 9. Indirectness 10. Hospitality

16 Management Approaches Affected by Cultural DiversityCentralized vs. Decentralized decision making Cultural Diversity Informal vs. formal procedures Safety vs. risk High vs. low organizational loyalty Individual vs. group rewards Cooperation vs. competition Sort-term vs. long-term horizons Stability vs. innovation

17 Summary of what we learned last weekIntroduction to the course of cross-cultural management and our international teaching team Goals for Cross-cultural management Nature of culture

18 We will learn today A model of culture: concentric circlesComparing culture as a normal distribution Values in culture Hofstede’s cultural dimensions

19 A model of culture: concentric circlesOuter layer: observable, e.g. language, food, buildings, art. Middle layer: helps people understand how they should behave. Inner layer: intangible, helpful for problem-solving and well interactions with other people. Explicit artifacts and products of the society Implicit, basic assumptions that guide people’s behavior Norms and values that guide the society

20 Comparing Cultures as Overlapping Normal DistributionChinese Culture U.S. Culture ? ? Chinese culture and American culture have quite different norms and values. The normal distribution curves for the two cultures have only limited overlap. When looking at the tail ends of the two curves, it is possible to identify stereotypical views held by Chinese about Americans and Americans about Chinese. Give some examples.

21 Stereotyping from the Cultural Extremes: Brugha and Du’s researchHow Americans see the Chinese in community avoid confrontation (keep in harmony) respect for authorities and seniors How Chinese see Americans individualism face confrontation (arguments and debates) respect for achievements Chinese Culture U.S. Culture

22 Values in Culture Values: basic convictions that people have regarding what is right and wrong, good and bad, important and unimportant. Value differences and similarities across cultures: P 10: “common personal values” U.S. Values and possible alternatives Values in transition: work values change over time.

23 Dominant Western Values in WorkforceCareer Stage Entered the Workforce Approximate Current Age Dominant Work Values 1. Protestant Work Ethic 2. Existential 3. Pragmatic 4. Generation X Mid-1940s to Late 1950s 1960s to Mid-1970s Mid-1970s to Mid-1980s through 1990s 50 to 65 35 to 50 35 to 35 Under 25 Hard working; loyal to firm; conservative Nonconforming; seeks autonomy; loyal to self Ambitious, hard worker; loyal to career Flexible, values leisure; loyal to relationships Workers who grew up influenced by the Great Depression, World War II, U.S. leadership in world manufacturing, the Andrews sisters, and the Berlin blockade entered the workforce from the mid-1940s to the late 1950s. They believed in the Protestant work ethic. Once hired, they tend to be loyal to an employer. They are likely to value family security and a comfortable life. Employees who entered the workforce from the 1960s to the mid-1970s were influenced by John F. Kennedy, the civil rights movement, the Beatles, and the war in Vietnam. They brought with them a large measure of the “hippie ethic” and existential philosophy. Quality of life is more important to them than money and possessions. They value autonomy, freedom, and equality. Those who entered the workforce from the mid-1970s through the mid-1980s reflect society’s return to more traditional values but with a greater emphasis on achievement and material success. They were influenced by Ronal Reagan, the defense build-up, dual-career households, and $150,000 starter homes. They are pragmatists who believe that ends can justify means. A sense of accomplishment and social recognition rank high for them. The lives of the members of Generation X have been shaped by globalization, the fall of Communism, MTV, AIDS, and computers. They value flexibility, life options, job satisfaction, family, and relationships. Money is important as an indicator of career performance, but they are willing to trade off leisure time for increases in salary, titles, security, and promotions.

24 Chap1-6 Dimensions of culture

25 Hofstede’s Cultural DimensionsDutch researcher Geert Hofstede found there are four dimensions of culture. Hofstede’s initial data: questionnaire surveys with over respondents from over 70 different countries who worked in the local subsidiaries of IBM. The fifth dimension was added later. Criticized because of its focus on just one company. Popular in the research field of cross-cultural management.

26 Hofstede’s Five Cultural Dimensions Power DistanceUncertainty Avoidance Individualism Masculinity Long-Term Orientation Hofstede’s Five Cultural Dimensions According to Hofstede, culture can be classified according to five dimensions. Power distance is the extent to which people accept unequal distributions of power. In higher power distance cultures, there is a wider gap between the powerful and the powerless. Uncertainty avoidance is the extent to which the culture tolerates ambiguity and uncertainty. High uncertainty avoidance leads to low tolerance for uncertainty and a search for absolute truths. Individualism is the extent to which either individuals or closely-knit social structures are the basis for social systems. Individualism leads to self-reliance and individual achievement. Masculinity is the extent to which assertiveness and independence are valued. High masculinity fosters high sex-role differentiation and focuses on ambition, independence, and material goods. Long-term orientation is the extent to which people focus of the past, the present, or the future. Present orientation focuses on short-term performance. Hofstede’s five dimensions can help managers classify cultures and predict organizational and managerial styles. But while his model provides a general ranking for a country, there may be many differences among the groups within a country. 10

27 Low: people treated as equals despite social status Power Distance: the extent to which less powerful members of organizations accept that power is distributed unequally. Low: people treated as equals despite social status High: people accept authority relations Uncertainty avoidance: the extent to which people feel threatened by ambiguous situations and have created beliefs and institutions that try to avoid these. Low: prefer few formal rules High: want clear behavioral guides

28 A bipolar continuum Low: group behavior importantIndividualism/collectivism: the tendency of people to look after themselves and their immediate family only (belong to groups or collectives and to look after each other in exchange for loyalty). Low: group behavior important High: individual behavior important A bipolar continuum Hofstede measured this cultural difference on a bipolar continuum with individualism at one end and collectivism at the other. Individualism Individualism Individualism Collectivism Collectivism

29 Masculinity/femininity: a situation in which the dominant values in society are success, money, and things (caring for others and the quality of life). Low: cooperation; friendly atmosphere; employment security; low stress; warm interpersonal relationships. High: competition; challenge; recognition; wealth; advancement; high stress; tight control. A continuum Hofstede measured this dimension on a continuum ranging from masculinity to femininity. Masculinity Femininity

30 Low: respect for tradition, personal stability, focused on the past Long–term orientation: value placed on persistence, status, thrift Low: respect for tradition, personal stability, focused on the past High: perseverance, thrift, focused on the future This dimension was added to depict the influence of Confucianism in Asia. This dimension is similar to “Adjusting” proposed by Brugha and Du.

31 Examples of Cultural DimensionsCountry Power Distance Individualism* Masculinity** Uncertainty Avoidance Long-term Orientation*** China High Low Moderate France Germany Hong Kong Indonesia Japan Netherlands Russia United States West Africa Different countries have different scores in terms of Hofstede’s cultural dimensions. * A low score is synonymous with collectivism ** A low score is synonymous with masculinity *** A low score is synonymous with a short-term orientation

32 Additional FrameworksTwo additional perspectives, of social/cross-cultural psychologists merit attention: Markus & Kitayama: Independent & Interdependent Construals Triandis: Individualism-Collectivism

33 Vertical & Horizontal Individualism & CollectivismHarry Triandis: Combination of Individualism vs. collectivism and power & achievement vs. benevolence & universalism VI: achievement + individualism (USA) HI: universalism + individualism (Sweden) VC: power + collectivism (India) HC: benevolence + collectivism (Israel; rare)

34 Schwartz’s Values Universalism Benevolence Conformity & traditionSecurity Power Achievement Hedonism Stimulation Self Direction

35 Schwartz’s Value Map

36 Empirical test of the Theory75,000 + respondents, varied samples in 68 countries Instrument lists 57 abstract value items “How important is each item as a guiding principle in your life?”

37 Tasks in the next session:Students’ talks and presentations Discussion in groups: how to learn Cross-cultural management? Assignment after class: Read a paper on Hofstede’s cultural dimensions.

38 Preview Integrating Hofstede’s cultural dimensionsAttitudinal dimensions of culture Trompenaars’s cultural dimensions Integrating culture and management

39 Chap1-7 Attitudinal Dimensions of CultureWork Value and Attitude Similarities Research has revealed many similarities in both work values and attitudes Ronen and Kraut Smallest space analysis (SSA) - maps the relationship among countries by showing the distance between each on various cultural dimensions Can identify country clusters Ronen and Shenkar Examined variables in four categories Importance of work goals Need deficiency, fulfillment, and job satisfaction Managerial and organizational variables Work role and interpersonal orientation

40 A Synthesis of Country Cultures

41 GLOBE Project Multi-country study and evaluation of cultural attributes and leadership behavior Are transformational characteristics of leadership universally endorsed? 170 country co-investigators 65 different cultures 17,500 middle managers 800 organisations

42 GLOBE Project What traits are universally viewed as impediments to leadership effectiveness? Based on beliefs that Certain attributes that distinguish one culture from others can be used to predict the most suitable, effective and acceptable organizational and leader practices within that culture Societal culture has direct impact on organizational culture Leader acceptance stems from tying leader attributes and behaviors to subordinate norms

43 GLOBE Cultural Variable ResultsVariable Highest Medium Lowest Ranking Ranking Ranking Assertiveness Spain, U.S. Egypt, Ireland Sweden, New Zealand Future orientation Denmark, Canada Slovenia, Egypt Russia, Argentina Gender differentiation South Korea, Italy, Brazil Sweden Denmark Egypt Uncertainty avoidance Austria, Denmark Israel, U.S. Russia, Hungary Power distance Russia, Spain England, France Demark, Netherlands Collectivism/Societal Denmark, Hong Kong, U.S. Greece, Hungary Singapore In-group collectivism Egypt, China England, France Denmark, Netherlands Performance orientation U.S., Taiwan Sweden, Israel Russia, Argentina Humane orientation Indonesia, Egypt Hong Kong, Germany, Spain Sweden

44 Chap1-8 Trompenaars’ Cultural DimensionsResearch produced five cultural dimensions that are based on relationship orientations and attitudes toward both time and the environment Universalism vs. Particularism Universalism - belief that ideas and practices can be applied everywhere in the world without modification Focus on formal rules and rely on business contacts Particularism - belief that circumstances dictate how ideas and practices should be applied and something cannot be done the same everywhere Focus on relationships, working things out to suit the parties

45 Trompenaars’ Cultural Dimensions (cont.)Individualism vs. Communitarianism Individualism - people regard themselves as individuals Rely on individuals to make decisions Communitarianism - people regard themselves as part of a group Seek consultation and mutual consent before making decisions Neutral vs. Emotional Neutral - culture in which emotions are held in check People try not to show their feelings Emotional - culture in which emotions are expressed openly and naturally People smile, talk loudly, greet each other with enthusiasm

46 Trompenaars’ Cultural Dimensions (cont.)Specific vs. Diffuse Specific - culture in which individuals have a large public space they readily share with others and a small private space they guard closely and share with only close friends and associates People often are open and extroverted Work and private life are separate Diffuse - culture in which both public and private space are similar in size and individuals guard their public space carefully, because entry into public space affords entry into private space as well People often appear indirect and introverted, and work and private life often are closely linked

47 Trompenaars’ Cultural Dimensions (cont.)Achievement vs. Ascription Achievement - culture in which people are accorded status based on how well they perform their functions Ascription - culture in which status is attributed based on who or what a person is For example, status may be accorded on the basis of age, gender, or social connections Time Sequential approach to time - people do one thing at a time, keep appointments strictly, follow plans to the letter Synchronous approach - people do more than one thing at a time, appointments are approximate

48 Trompenaars’ Cultural Dimensions (cont.)Environment Inner-directed People believe in controlling environmental outcomes Outer-directed People believe in allowing things to take their natural course Cultural Patterns or Clusters Defined groups of countries that are similar to each other in terms of the five dimensions and the orientations toward time and the environment

49 Trompenaars’ Cultural GroupsAnglo cluster Relationship United States United Kingdom Individualism x x Communitarianism Specific relationship x x Diffuse relationship Universalism x x Particularism Neutral relationship x Emotional relationship x Achievement x x Ascription

50 Trompenaars’ Cultural GroupsAsian cluster Relationship Japan China Indonesia Hong Kong Singapore Individualism Communitarianism x x x x x Specific relationship Diffuse relationship x x x x x Universalism Particularism x x x x x Neutral relationship x x x x Emotional relationship x Achievement Ascription x x x x x

51 Trompenaars’ Cultural GroupsLatin American cluster Relationship Argentina Mexico Venezuela Brazil Individualism x x x Communitarianism Specific relationship Diffuse relationship x x x x Universalism Particularism x x x x Neutral relationship x x x Emotional relationship x Achievement x x Ascription x x

52 Trompenaars’ Cultural GroupsLatin-European cluster Relationship France Belgium Spain Italy Individualism x Communitarianism x x x Specific relationship x x Diffuse relationship x x Universalism x x x Particularism x Neutral relationship x Emotional relationship x x x Achievement x Ascription x x x

53 Trompenaars’ Cultural GroupsGermanic cluster Relationship Austria Germany Switzerland Czechoslovakia Individualism x Communitarianism x x x Specific relationship x x x Diffuse relationship x Universalism x x x x Particularism Neutral relationship x x Emotional relationship x x Achievement x x x Ascription x

54 Culture Maps - FrameworksEdward T. Hall Geert Hofstede Kluckhohn & Strodbeck Trompenaars Value Patterns Variations in Value Orientations Culture Elements Value Patterns universalism– particularism collectivism– individualism affective–neutral relationships specificity–diffuseness achievement– ascription time orientation Internal–external control & Int’l. business practice relation to nature orientation to time belief about human nature mode of human activity relationships space & Int’l. business practice time space things friendships agreements & interpersonal behavior power risk individualism masculinity long term orientation & management theories - practice

55 Chapter 2 Managing Across CulturesChapter 2(1) _ Global Culture…2 Chapter 2(2) _ Multicultural Teams…11 Chapter 2(3) _ Motivation in a Global Context…36 Chapter 2(4) _ Decision Making…51 Chapter 2(5) _ Leadership…68 Chapter 2(6) _ Global HRM…92

56 Chapter 2(1) _Global Culture

57 CULTURAL MESSAGES COME FROM MULTIPLE SOURCESDomestic International Global although most common challenges are addressed by nations, a global civil society is emerging

58 PEOPLE LOOK AT ALTERNATIVE ENTITIES FOR CULTURAL DIRECTIONAffiliative groups e.g., ethnic groups Nongovernmental organizations, e.g., the Women’s League for Peace and Freedom Religious groups Regional associations, e.g., Economic Union Business organizations As I mentioned earlier, people look to different groups for direction when they are confused: it is important to recognize that they look to global businesses for direction—this is a new role of business.

59 Multiple messages and sources create CONFUSION AND UNCERTAINTYLeading to new questions national cultures are less well able to answer but In a global society, we don’t have a sense of the appropriate rules by which all can live

60 TRANSITION TIME? All of UsAre we at a point where nationality is less important to culture than in the past? All of Us

61 WE SEE THAT SOME VALUES ARE COVERGING, OTHERS ARE NOTThe Planet Project The Roper Poll of Values The World Values Survey The GLOBE Project The Planet Project and the Roper Poll of Values Polls that report public opinion are not as rigorous as studies reported above. Nevertheless, they provide some insight about worldwide beliefs. In 2000, Minnesota Manufacturing and Mining (3M) initiated the Planet Project, an interactive Internet-based poll to which hundreds of thousands of people worldwide responded. Volunteers also conducted face-to-face interviews in 115 nations to include opinions from those who are not Internet connected. Findings thus far show that people around the world are very concerned about their self-image and with projecting a youthful appearance. A surprising finding is that the more educated a person is, the more likely a belief in God (Johnson, 2001). Roper Starch Worldwide also asked 30,000 people worldwide to rank 57 personal values in order of importance. Of the top five values overall, protecting the family was first, followed by honesty, health and fitness, self-esteem and self-reliance. Other values rated highly were freedom, stable relationships, and faith (World Trends, 2001). Faith was ranked most highly in nations that are predominately Muslim, e.g., Indonesia, Egypt, and Saudi Arabia. The World Values Survey Introduced in 1981 the World Values Survey examines the values of 65 societies (Ingelhart and Baker, 2000) or about 80 percent of the world's population. Results show that economic development has a powerful relationship with cultural values. That is, people from low-income societies differ significantly from those in high-income countries on two dimensions: traditional vs. secular-rational values and survival vs. self-expression values.

62 GLOBE RESPONSES ON GENDER EGALITARIANISM SHOWS COVERGENCE ON “SHOULD BE”Details on the GLOBE project are in Chapter 14. 160 social scientists and management scholars from 62 cultures representing all major regions throughout the world are engaged in this long-term programmatic series of cross-cultural leadership studies. GLOBE is a multi-method multi-phase research program designed to test a cross-level integrated theory of the relationship between culture and leadership effectiveness. They looked at 62 cultures, grouping them by similarities, e.g., Anglo (this included white S. Africa), Latin Ameican, Latin Europe (French speaking Switzerland), Southern Asia, Germanic Europe, and the Middle East. Over 17,000 middle managers from over 900 corporations in food processing, finance, and telecommunications industries in 62 cultures participated in GLOBE surveys. GLOBE measures both cultural practices (as is) and cultural values (should be). Project GLOBE is a multi-method multi-phase research program to test relationships between culture and leadership effectiveness. Over 160 social scientists and management scholars participate in this series of studies. By 2004, researchers had gathered information from over 17,000 middle managers from more than 900 corporations in food processing, finance, and telecommunications industries in 62 cultures. These managers answered questions according to both cultural practices (as is) and cultural values (should be). Results published in the first comprehensive report on GLOBE (House et al., 2004) reflect variations in management practices worldwide. However, when asked to indicate what “should be,” respondents showed convergent views. For example, on gender egalitarianism—the degree to which a collective minimizes gender inequality—managers indicated that gender inequalities should be far less than now practiced. Similarly on humane orientation—the degree to which a collective encourages and rewards individuals for being fair, altruistic, generous, caring, and kind to others—the mean score on practices was a full point lower than the mean score on what “should be” practiced. These results suggest that current practices among managers are divergent cross-culturally, but values may be converging. A premise to be tested in later phases of the GLOBE project is the extent to which effectiveness is a function of the interaction between leader attributes and organizational contingencies (House et al., 2002).

63 GLOBE RESPONSES ON HUMANE ORIENTATION ALSO SHOWS COVERGENCE ON “SHOULD BE”

64 QUESTIONS OF GLOBAL AND LOCAL CULTURESWill global culture replace or exist with local cultures? Will global culture bring positive or negative outcomes? I believe that national cultures will endure, but that global cultures will emerge alongside them. In particular, I think there will some day be a global business culture—we see that developing now with global rules of conduct, global rules of trade (WTO), global approaches to environmental use, etc.

65 Chapter 2(2)- Multicultural Teams

66 Group Two or more interacting individuals who come together to achieve some objectives. Groups can be either formal or informal, and further subclassified into command, task, interest, or friendship categories.

67 Team A specific type of group where an emphasis is put on some level of member interdependence and on achievement of common goals All teams are groups Some groups are just people assembled together Teams have task interdependence whereas some groups do not (e.g., group of employees enjoying lunch together)

68 Reasons for Team PopularityOutperform individuals on tasks requiring multiple skills, judgment, and experience Better utilization of employee talents More flexible and responsive to changing events Facilitate employee participation in operating decisions Effective in democratizing the organization and increasing employee involvement and motivation

69 Basic Group Concepts Group Roles Group Norms Acceptable Standardsof Behavior Shared by the Members of a Group Expected Patterns of Behavior Based on a Given Position in a Social Unit Group Roles Group Norms Groups are not unorganized; rather, they have a structure that shapes the behavior of their members. When we play a role, we engage in a set of expected behavior patterns that are attributed to occupying a given position in a social unit. Based on role research, we can conclude the following: (1) People play multiple roles. (2) People learn roles from the stimuli around them. (3) People shift roles rapidly according to situational demands. (4) People experience conflict when one role contradicts another. Acceptable standards of group behavior that are shared by the group’s members are called norms. When accepted by the group, norms influence the group’s behavior with a minimum of external controls. Groups will exert pressure upon members to bring their behavior into conformity with the standards of the group. Since members desire acceptance by the group, they are susceptible to these conformity pressures. Solomon Asch’s classic study demonstrated the following: People desire to be one of the group and to avoid being different, so they feel pressure to conform.

70 Cohesiveness Social-Oriented Cohesiveness: The degree to which members of the group are attracted to each other and motivated to stay in the group Task-Oriented Cohesiveness: The degree to which group members work together, cooperate and coordinate their activity in order to achieve group goals

71 Team Effectiveness ModelTask characteristics Team size Team composition Team Design Achieve organizational goals Satisfy member needs Maintain team survival Team Effectiveness Team development Team norms Team roles Team cohesiveness Team Processes Organizational and Team Environment Reward systems Communication systems Physical space Organizational environment Organizational structure Organizational leadership

72 Groups Across CulturesTwo cultural dimensions are especially relevant: Individualism-Collectivism Power Distance Also Uncertainty Avoidance; e.g., potential for Role Conflict (esp. in multi-functional teams)

73 The Challenge in Shaping Team PlayersGreatest where... The national culture is highly individualistic Introduced into organizations that historically value individual achievement Less demanding... Where employees have strong collectivist values, such as Japan or Mexico In new organizations that use teams as their initial form for structuring work

74 Cross-Cultural DifferencesCross–cultural differences in intergroup processes Collectivistic cultures Expect little expression of conflict; favor suppressing conflict Prefer to personalize interaction; focus on people, despite what group they represent Group membership is an important part of identity and interaction

75 Power Distance and SDWTsNicholls et al. (1999) study of SDWT in Mexico: Why are teams failing in a highly collectivist culture such as Mexico? Major challenges in implementing SDWTs Workers expect to exercise little control over work and not to be involved in decision making Expect clear instructions from the top and are not highly motivated by opportunity to initiate and take larger responsibility Can SDWT work in high-PD cultures? How?

76 Interpersonal RelationshipsIndividualists tend to have more friends, but with lesser intensity level; Collectivists tend to have less friends, but with higher intensity level. Individualists are less suspicious towards out-group members and easier to make initial contact; Collectivists have stronger bonds with in-group members

77 Differential Group ProcessesConformity: who is more conforming? Formal/regulated participation vs. spontaneous Social loafing versus social striving Preferences for group vs. individual rewards Equality (‘you deserve what you get’) vs. Equity (‘you get what you deserve’) vs. Need based decisions (‘to all according to their needs’)

78 Conformity Cross–cultural variations in tendency to accept group pressure for conformity to group norms Japanese encourage high conformity to norms of a group that has the person's primary loyalty German students (in some experimental research) showed a lower tendency to conform Moderate conformity among people in Hong Kong, Brazil, Lebanon, and the United States

79 Teams’ Cultural CompositionCultural Diversity: the number of different cultures represented in the group; Cultural Norms: the orientations of the specific cultures represented in the group toward group dynamics and processes; and Relative Cultural Distance: the extent to which group members are culturally different from each other

80 Surface and Deep DiversityIn multicultural teams, diversity can be in the form of: Surface-level (black-American; Caucasian-American; French and Vietnamese) and/or Deep-level (Irish and English; Singaporean and Chinese; N. and S. Africans)

81 Dynamics of Team DiversitySocial Context Org. Context Group Dynamics Affective Reactions Cohesion Satisfaction Commitment Team Behaviours Communication Conflict Cooperation Long-term Conseq. Performance Promotion Turnover Diversity Surface Deep

82 Jackson, Joshi & Erhardt (2003)Surface-level diversity has more immediate impact and is influential in early-stage/newly formed teams while deep-level becomes more important over time and its effects last longer. Diversity, in general, and cultural/ethnic diversity in particular, have mixed effects on team processes and performance; Less effect on simpler, motor-based tasks; more effect on complex, interdependent teamwork

83 Earley & Mosakowski (2000) Studied effects of heterogeneity in transnational teams using experimental and field settings Reasoned that the effects of national heterogeneity on team performance is non-linear; Found that in the early stages, homogenous teams (those with only one major national group identity) outperformed both moderately heterogeneous (groups with two different sub-group identities) and highly heterogeneous (no clear sub-group identities exist) teams.

84 Earley & Mosakowski (2000) In the longer term, high-heterogeneous teams’ performance increased as they managed to create a hybrid-culture; Such hybrid culture was not created in moderately heterogeneous teams, whose performance was lower than both high and low heterogeneity teams. Team processes mediated the effects of heterogeneity on team performance, such that: In homogenous groups, members perceived many similarities between themselves (remember SIT?); trust, shared mental models and open communication developed early on in the team’s life

85 Earley & Mosakowski (2000) In moderately heterogeneous teams, a dynamic of ‘us vs. them’ prevailed, with the two sub-groups sticking to themselves in times of conflict, resulting in little cross sub-group cooperation; In highly heterogeneous teams, as time passed, members go to know each other better and since there were no dominant sub-groups, they were free to form a ‘hybrid culture’-unique to their team and overarching each members’ national identity. Implications for joint ventures and projects where two cultures (national or organizational) get together to try to create a cooperative structure

86 Diversity and Teams Overall, diversity causes process lossesCan be beneficial if team overcomes these losses over time Depends on organizational culture and top-management support Highly heterogeneous and highly homogenous teams work better than mid-range ones Fault lines in teams lead to rivalry coalitions => decrease effectiveness

87 Conditions for EffectivenessMore Effective Less Effective Task Innovative Routine Stage Divergence (earlier) Convergence (later) Conditions Differences Recognized Differences Ignore Task-based member selection Culture-base members selection Pluralism Ethnocentrism Equal Power Cultural Dominance Superordinate goals Individual goals External feedback No feedback/autonomy

88 Some Implications Investment in diverse teams is more sensible for the longer-term, for complex tasks and when team members are (relatively) pluralistic More careful task design is needed Positive feedback, early on Preparation and training, through conceptual and experiential approaches is recommended Strive to create a third culture through superordinate goals and neutralization of differences

89 Diversity: Beyond the ObviousSeemingly culturally similar team members may have the hardest time to get along: need to take into account other variables besides culture (history, class) Idiosyncratic cultural variables, e.g., intellectual style (Russians vs. N. Americans) Prior experience with different cultures plays important role (usually for the better) Virtual Teams: added complexity

90 Chapter 2(3)-Motivation in a Global Context

91 The Basic Motivation ProcessIntroduction to Motivation Motivation Psychological process through which unsatisfied wants or needs lead to drives that are aimed at goals or incentives The Basic Motivation Process Unsatisfied need Drive toward goal to satisfy need Attainment of goal (need satisfaction)

92 Introduction to MotivationNeed Theories Cognitive theories Expectancy theory: describes internal processes of choice among different behaviors Equity theory: describes how and why people react when they feel unfairly treated Goal setting theory: focuses on how to set goals for people to reach Behavioral theory Behavior modification: focuses on observable behavior, not internal psychological processes

93 Basic Assumptions The Universalist AssumptionAll people are motivated to pursue goals they value Specific content of the goals that are pursued will be influenced by culture Movement toward market economies may make motivation more similar in different countries

94 Motivation Theories Are Culture BoundNeed for Achievement Hierarchy of Needs Goal-Setting Theory Most theories of motivation were developed in the United States by Americans and about Americans. Maslow’s hierarchy of needs argues that people start at the physiological level and move up the hierarchy in this order: physiological, safety, social, esteem, and self-actualization. This hierarchy aligns with American culture. In cultures where uncertainty avoidance characteristics are strong, security needs would be on top of the hierarchy. In cultures that score high on quality-of-life needs, social needs would be on top. The view that high achievement acts as an internal motivator presupposes two cultural characteristics: a willingness to accept a moderate degree of risk and a concern with performance. This combination is prevalent in Anglo American countries. Yet these characteristics are relatively absent in countries such as Chile or Portugal. Goal-setting theory is also culture bound. Its key components align reasonably well with U.S. culture. It assumes that subordinates will be reasonably independent, that managers and subordinates will seek challenging goals, and that performance is considered important by both. Goal-setting theory is not likely to increase motivation in countries in which the opposite conditions exist, such as Chile, France, and Portugal.

95 Attitudes and PersonalityPersonality characteristics People in individualistic cultures (United States) have stronger need for autonomy than people in group–oriented cultures (Japan) People in cultures that emphasize avoiding uncertainty (Belgium, Peru) have stronger need for security than people in cultures that are less concerned about avoiding uncertainty (Singapore, Ireland)

96 Need Theories of MotivationConcept of needs holds across cultures People from different cultures may express and satisfy needs differently Importance of needs in Maslow's need hierarchy United States: self–actualization Latin America: security, affiliation France and Germany: need for security New Zealand: belongingness and love McClelland: needs for affiliation, power and achievement

97 International Aspects of Job DesignHerzberg: Two Factor Theory Individual and group–based job design U.S. managers have mostly used individual approaches to job design Recent shifts to group–based approaches Managers in other industrialized countries have mainly emphasized group–based job design

98 Job Design (Cont.) Changing specific job characteristicsBelgium, Mexico, Greece, Thailand: not likely to accept efforts to increase autonomy and task identity French managers particularly dislike recommendations to decentralize decision authority. Subordinates do not expect them to do so Quality circles: big success in Japan, but only partial in the US

99 Cognitive and Behavioral Theories of MotivationTwo assumptions that could restrict use of these theories outside the U.S. Individual controls decisions about future actions Manager can deliberately shape the behavior of people

100 Cognitive and Behavioral Theories of MotivationBoth assumptions reflect U.S. values of free will, individualism, individual control Cultural contrasts Muslim managers believe something happens mainly because God wills it to happen Hong Kong Chinese believe luck plays a role in all events

101 Cognitive and Behavioral TheoriesExpectancy theory's validity in other cultures Japanese female life insurance sales representatives responded to commission system as expected Russian textile workers Linked valued extrinsic rewards to worker performance Productivity increased as the theory predicts Generally, expectancy theory best explains motivation of people in cultures that emphasize internal attribution

102 Cognitive and Behavioral Theories (Cont.)Equity theory: complex cross–cultural effects Reward allocation decisions followed equity theory premises in U.S., Russian, and Chinese samples Other studies Chinese emphasized seniority in their reward decisions more than Americans. Eastern European transition economies: endorsed positive inequity more than American students

103 Culture & Motivation Research on goal setting theory in several countries Results consistent with U.S. work that formulated the theory Some cultural differences U.S. students not affected by how goals were set Israeli students performed better when goals were set participatively; consistent with culture of cooperation

104 Idiosyncratic FactorsBeyond cultures’ variance along the major cultural value dimensions, there are specific aspects anchored in nation’s history and expressed through its symbols and language. Ignoring such factors may render motivational techniques ineffective or even result in de-motivation; e.g.: Slay the Dragon!!

105 Chap 2(4)- Decision Making across Cultures

106 Decision Making Process of choosing a course of action among alternatives

107 Various Factors * Time Orientation Deciding for the short/long term?How long to make a decision? Polichronic or monochronic style? * Who decides: Groups vs. Individuals * Voting vs. Consensus based decisions * Process: Participative vs. Autocratic

108 Value of Rationality Strong preference for rational D.M. vs.Occasional or low value on rationality; In some cultures more emphasis on: Emotions Religion Ideology

109 Rational Decision MakingThe Rational Approach assumes that Managers follow a systematic, step-by-step process. Organization is economically based and is managed by decision makers who are entirely objective and have complete information. It assumes that rational choices are: Consistent Value-maximizing Within specified constraints

110 The Six-Step Rational Decision-Making Model1. Define the problem 2. Identify decision criteria 3. Weight the criteria 4. Generate alternatives 5. Rate each alternative on each criterion 6. Compute the optimal decision

111 Cultural Contingencies in Decision MakingStep 1. Problem Recognition Problem solving; change Situation acceptance 2. Information Search Gathering facts Gathering ideas and possibilities 3. Construction of Alternatives New, future oriented based on change Past/present/future based on stability 4. Choice Individual level; delegation of responsibility; fast Group level; by senior management; slowly 5. Implementation Slow; top-down Fast; broad participation

112 Case Study: The Road to Hell (p. 512)What mistakes did John Baker Made? Why did he not realize his mistake when it occurred? What would you recommend that Baker do now? What do you learn from this case about human resource management across different nations?

113 Stages of Moral DevelopmentStage Description Level 1. Sticking to rules to avoid physical punishment 2. Following rules only when it’s in your immediate interest 3. Living up to what is expected by people close to you 4. Maintaining conventional order by fulfilling obligations to which you have agreed 6. Following self-chosen ethical principles, even if they violate the law 5. Valuing rights of others; upholding non-relative values and rights regardless of the majority’s opinion Principled Conventional Pre-conventional Adapted from L. Kohlberg, “Moral Stages and Moralization: The Cognitive-Developmental approach,” pages in Moral Develop and Behavior: Theory, Research, and Social Issues, ed. T. Lickona (New York: Holt, Rinehart & Winston, 1976).

114 Three Different Criteria in Making Ethical ChoicesUtilitarian Criterion - made solely on basis of outcomes or consequences Focus on Rights - made consistently with fundamental liberties and privileges Focus on Justice - requires imposing and enforcing rules fairly and impartially for equitable distribution of benefits and costs

115 Ethical Aspects of DecisionsMultinational firms face many ethical questions and issues Operate in many countries; subject to the laws of those countries Legal and social context of globally oriented organizations can present their managers with ethical dilemmas

116 Ethical Aspects of DecisionsTwo ethical views Cultural relativism Ethical realism Multinational organization

117 Ethical Aspects of DecisionsEthical views: Cultural relativism Cultural relativism refers to differences in ethical values among different cultures Premise: right and wrong should be decided by each society's predominant ethical values Cultural relativists base their argument on three points

118 Ethical Aspects of DecisionsCultural relativism (cont.) Three points Moral judgments are statements of feelings and opinions; neither wrong nor right Moral judgments are based on local ethical systems; cannot judge right or wrong across cultures Prudent approach: do not claim an action is either right or wrong

119 Ethical Aspects of DecisionsCultural relativism (cont.) Managers should behave according to local ethical systems, even if behavior violates home country ethical system Many philosophers reject cultural relativism's argument that codes of ethics cannot cross national boundaries Agree that countries vary in defining right and wrong

120 Ethical Aspects of DecisionsEthical realism Morality does not apply to international transactions Because no power rules over international events, people will not behave morally Because others will not behave morally, one is not morally required to behave ethically

121 Ethical Aspects of DecisionsInternational ethical dilemmas Goods made in a country with no child labor laws Goods made in a country with child labor laws that are not enforced Changing the behavior of local people Making small payments that are allowed under the company’s national law

122 Chapter 2(5)-Leadership

123 Definitions There are almost as many definitions of leadership as there are theories…some of the more common ones are: Ability to influence a group toward the achievement of goals. The process whereby one individual influences other group members towards the attainment of defined group or organisational goals. The process of creating vision for others and having the power to translate it into a reality and sustain it.

124 Foundation for LeadershipLeadership Behaviors and Styles The use of work-centered behavior designed to ensure task accomplishment. Authoritarian Leadership Paternalistic Leadership The use of work-centered behavior coupled with a protective employee centered concern. Participative Leadership The use of both work- or task-centered and people centered approaches to leading subordinates.

125 Leader–Subordinate InteractionsAuthoritarian Leader Subordinate Subordinate Subordinate One-way downward flow of information and influence from authoritarian leader to subordinates.

126 Leader–Subordinate InteractionsPaternalistic Leader Subordinate Subordinate Subordinate Continual interaction and exchange of information and influence between leader and subordinates.

127 Leader–Subordinate InteractionsParticipative Leader Subordinate Subordinate Subordinate Continual interaction and exchange of information and influence between leader and subordinates.

128 Contingency Theories Leaders use various leadership styles/behaviours;Quality of leadership experience depends on several situational factors, including followers and task type. Path-Goal Model - Leader assists followers in attaining goals and ensures goals are compatible with overall objectives

129 Path-Goal Theory A theory of leadership suggesting that subordinates will be motivated by a leader only to the extent they perceive this individual as helping them to attain valued goals.

130 Path-Goal Theory Four basic leadership styles:Instrumental (directive): An approach focused on providing specific guidance and establishing work schedules and rules. Supportive: A style focused on establishing good relations with subordinates and satisfying their needs. Participative: A pattern in which the leader consults with subordinates, permitting them to participate in decisions. Achievement Oriented: An approach in which the leader sets challenging goals and seeks improvements in performance.

131 Path-Goal Theory Environmental contingency factors Task structureFormal authority system Work group Leader behavior Directive Supportive Participative Achievement oriented Outcomes Performance Satisfaction Subordinate contingency factors Locus of control Experience Perceived ability

132 Leadership Core values of country’s culture often define type of leadership behavior that is acceptable In high PD, an emphasis on hierarchical relationships—directive approaches accepted; Hong Kong, Latin American countries; Russia In low PD, hierarchical relationships are not valued —supportive (or participative) approaches accepted; Austria, Scandinavia, Israel

133 Leadership Individualism-CollectivismLeader as a paternal figure vs. leader as an expert Degree to which intervention of leader in follower’s private lives is expected and accepted Masculine/Feminine Acceptance of women as leaders Accepted style for leaders Long-Term-Orientation Elect leaders for four years…or forty? Leader’s style: first among equals (China) or class of its own (Arab Countries)

134 GLOBE Project Multi-country study and evaluation of cultural attributes and leadership behavior Are transformational characteristics of leadership universally endorsed? 170 country co-investigators 65 different cultures 17,500 middle managers 800 organizations

135 GLOBE Project Which traits are universally viewed as impediments to leadership effectiveness? Based on beliefs that Certain attributes that distinguish one culture from others can be used to predict the most suitable, effective and acceptable organizational and leader practices within that culture Societal culture has direct impact on organizational culture Leader acceptance stems from tying leader attributes and behaviors to subordinate norms

136 Assertiveness Spain, U.S. Egypt, Ireland Sweden, New Zealand GLOBE Cultural Variable Results Variable Highest Medium Lowest Ranking Ranking Ranking Assertiveness Spain, U.S. Egypt, Ireland Sweden, New Zealand Future orientation Denmark, Canada Slovenia, Egypt Russia, Argentina Gender differentiation South Korea, Italy, Brazil Sweden Denmark Egypt Uncertainty avoidance Austria, Denmark Israel, U.S. Russia, Hungary Power distance Russia, Spain England, France Demark, Netherlands Collectivism/Societal Denmark, Hong Kong, U.S. Greece, Hungary Singapore In-group collectivism Egypt, China England, France Denmark, Netherlands Performance orientation U.S., Taiwan Sweden, Israel Russia, Argentina Humane orientation Indonesia, Egypt Hong Kong, Germany, Spain Sweden

137 Universal Leadership AttributesPositive Trustworthy Just Honest Charisma Inspiration & Vision Team-Orientation Excellence-Oriented Decisive Intelligent Negative Loner Non-Cooperative Ruthless Non-explicit Irritable Dictatorial

138 Leadership and ManagementNeed to bear in mind that leadership style is very much situation dependent: for example, in some situations (e.g., emergency) and in some organizational cultures, directive style will be accepted even in a country like the US; Participation is more likely if the basis of power is more achievement based (instrumental) than if it is ascribed (personal) and Degree of participation in decision making and leadership by subordinates vary cross-nationally

139 Leadership in the International ContextAttitudes of European Managers Toward Leadership Practices European managers tend to use a participative approach. Researchers investigated four areas relevant to leadership. Does the leader believe that employees prefer to be directed and have little ambition? (Theory X) OR Does the leader believe that characteristics such as initiative can be acquired by most people regardless of their inborn traits and abilities? (Theory Y) Capacity for Leadership and Initiative

140 Leadership in the International ContextAttitudes of European Managers Toward Leadership Practices Most evidence indicates European managers tend to use a participative approach. Researchers investigated four areas relevant to leadership. Capacity for Leadership and Initiative Does the leader believe that detailed, complete instructions should be given to subordinates and that subordinates need only this information to do their jobs? OR Does the leader believe that general directions are sufficient and that subordinates can use their initiative in working out the details? Sharing Information and Objectives

141 Leadership in the International ContextAttitudes of European Managers Toward Leadership Practices Most evidence indicates European managers tend to use a participative approach. Researchers investigated four areas relevant to leadership. Does the leader support participative leadership practices? Capacity for Leadership and Initiative Sharing Information and Objectives Participation

142 Leadership in the International ContextAttitudes of European Managers Toward Leadership Practices Most evidence indicates European managers tend to use a participative approach. Researchers investigated four areas relevant to leadership. Capacity for Leadership and Initiative Does the leader believe that the most effective way to control employees is through rewards and punishment? OR Does the leader believe that employees respond best to internally generated control? Sharing Information and Objectives Participation Internal Control

143 Japanese vs. U.S. Leadership StylesDimension Japan US Employment Often for life Often short-term Evaluation Slow, takes many years Fast: those not promoted often leave Career Paths Very general; based on rotations v. specialised; people stay in one area Dec. Making Group based By individual managers Control Mech. Implicit & informal; reliance on trust and goodwill Explicit; based on knowing the control mechanisms Responsibility Shared collectively Assigned individually Concern for employees Broad and covers the whole life limited to work-life

144 Differences in Middle Eastern and Western Management

145 Differences in Middle Eastern and Western Management

146 Leadership-Other IssuesEmphasis on Emotional Intelligence is especially important for leading cross-culturally Idiosyncratic effects & paradoxes: Moderately masculine Muslim and Hindu nations with traditional views on women…but, Israel, India, Pakistan and other exceptions Charismatic leadership is not universally accepted

147 Chapter 2(6)-GLOBAL HUMAN RESOURCES

148 HR Challenges of International BusinessResearchers asked “What are the key global pressures affecting human resource management practices in your firm currently and for the projected future?” Responses were: Deployment Knowledge and innovation dissemination Identifying and developing talent globally Page 465 Deployment: Easily getting right skills where needed regardless of geographic location. Knowledge and innovation dissemination: Spreading state-of-the-art knowledge and practices throughout the organization regardless of where they originate. Identifying and developing talent on a global basis: Identifying who can function effectively in a global organization and developing his or her abilities.

149 Global Staffing PressuresCandidate selections Assignment terms Relocation Immigration Culture and language Compensation Tax administration Handling spouse and dependent matters Page 466 Dealing with global staffing pressures like these is quite complex. For example, it involves addressing, on a global basis, activities including candidate selections, assignment terms and documentation; relocation processing and vendor management; immigration processing; cultural and language orientation and training; compensation administration and payroll processing; tax administration; career planning and development; and handling of spouse and dependent matters.

150 Economic Differences US $19.86 Mexico $2.46 Taiwan $5.98 UK $15.88Translate into differences in HR practices: Espousing ideals of free enterprise Wage costs vary Other labor costs vary: severance pay; holidays US $19.86 Page 467 Shown are hourly wages for production workers (converted into US dollars). There are other labor costs to consider. For example, there are wide gaps in hours worked. Portuguese workers average about 1,980 hours of work annually, while German workers average 1,648 hours. Several European countries, including the United Kingdom and Germany, require substantial severance pay to departing employees, usually equal to at least two years’ service in the United Kingdom and one year’s in Germany.19 Compared to the usual two or three weeks of U.S. vacation, workers in France can expect two days of paid holiday per full month of service per year, Italians usually get between four and six weeks off per year, and Germans get 18 working days per year after six months of service. Mexico $2.46 Taiwan $5.98 UK $15.88 Germany $29.01

151 International Labor RelationsUnion membership varies widely worldwide 24% 29% 80% 39% 44% Page 477 Firms opening subsidiaries abroad will find substantial differences in labor relations practices among the world’s countries and regions. This is important; remember that while union membership as a percentage of wage and salary earners is dropping in the U.S., it is still relatively high in most countries compared with the United States’ 14%: for example, Brazil, 44%; Argentina, 39%; Germany, 29%; Denmark, 80%; Japan, 24%; Egypt, 39%; and Israel, 23%. 39% 23% 14%

152 International StaffingMultinational corporations (MNC’s) use several types of international managers: Locals Expatriates Home-country nationals Third-country nationals Page 469 Locals are citizens of the countries in which they work. Expatriates are non-citizens of the countries in which they’re working. Home-country nationals are citizens of the country in which the multinational corporation has its headquarters. Third-country nationals are citizens of a country other than the parent or host country; e.g., a British executive in the Tokyo branch of a US multinational bank.

153 Sources of Human ResourcesHome Country Nationals Expatriate managers who are citizens of the country where the MNC is headquartered Expatriates Those who live and work away from their home country Citizens of the country where the MNC is headquartered Expatriates are useful for: starting up operations providing technical expertise helping the MNC maintain financial control over the operation Expatriates almost always were men Situation is changing Expatriates typically used in top management positions

154 Sources of Human ResourcesHost-Country Nationals Local managers who are hired by the MNC Used in middle- and lower-level management positions Nativization Requirement of host-country government that mandates employment of host-country nationals

155 Sources of Human ResourcesThird-Country Nationals (TCNs) Citizens of countries other than the one in which the MNC is headquartered or the one in which the managers are assigned to work by the MNC Found in MNCs that have progressed through the initial and middle stages of internationalization

156 Sources of Human ResourcesAdvantages of using TCNs Require less compensation Good working knowledge of the region Given home office experience, often can achieve objectives better than other types of managers Offer different perspectives

157 Failure Rates of International AssignmentsInternational assignment failure can cost hundreds of thousands of euros Page 468 Shown are the maximum failures of a country or region for international assignments International assignments are the heart of international HR, and it’s therefore disconcerting to see how often such assignments fail. U.S. expatriates’ assignments that end early (the failure rate) range from 16% to 50%, and the direct costs of each such failure can reach hundreds of thousands of dollars or more. European and Japanese multinationals reported lower failure rates, with only about one-sixth of Japanese multinationals and 3% of European multinationals reporting more than a 10% expatriate recall rate.

158 Why International Assignments FailPersonality Person’s intentions Family pressures Lack of cultural skills Other non-work conditions like living and housing conditions, and health care Page 469 Discovering why such assignments fail is therefore an important research task, and experts have made considerable progress. Personality is one factor. For example, in a study of 143 expatriate employees, extroverted, agreeable, and emotionally stable individuals were less likely to want to leave early. And the person’s intentions are important: For example, people who want expatriate careers try harder to adjust to such a life. Non-work factors like family pressures usually loom large in expatriate failures: In one study, U.S. managers listed, in descending order of importance for leaving early: inability of spouse to adjust, managers’ inability to adjust, other family problems, managers’ personal or emotional immaturity, and inability to cope with larger overseas responsibility. Managers of European firms emphasized only the inability of the manager’s spouse to adjust as an explanation for the expatriate’s failed assignment. Other studies similarly emphasize dissatisfied spouses’ effects on the international assignment. One expert said: The selection process is fundamentally flawed Expatriate assignments rarely fail because the person cannot accommodate to the technical demands of the job. The expatriate selections are made by line managers based on technical competence. They fail because of family and personal issues and lack of cultural skills that haven’t been part of the process.

159 Improving Failure Rates/SolutionsProvide realistic previews Have a careful screening process Improve orientation Provide good benefits Test employees fairly Shorten assignment length Page 469 Failure rates have dropped 9% over the last 10 years by stressing the items listed.

160 Important Predictors of SuccessFamily situation tops the list Flexibility/adaptability screening was high on results Use paper and pencil tests like the Overseas Assignment Inventory Previewing what changes an international assignee can expect Page 472 Many firms also use paper-and-pencil tests such as the Overseas Assignment Inventory. Based on 12 years of research with more than 7,000 candidates, the test reportedly identifies the characteristics and attitudes international assignment candidates should have. Realistic previews about the problems to expect in the new job (such as mandatory private schooling for the children) as well as about the cultural benefits, problems, and idiosyncrasies of the country are another important part of the screening process. The rule, say some experts, should always be to “spell it all out” ahead of time, as many multinationals do for their international transferees.

161 Selecting International ManagersTest for traits that predict success in adapting to new environments Job knowledge and motivation Relational skills Flexibility and adaptability Extra-cultural openness Family situation Predictive trait breakdown Page 472 Selecting managers for these assignments therefore sometimes means testing them for traits that predict success in adapting to new environments. One study asked 338 international assignees from various countries and organizations to specify which traits were important for the success of managers on foreign assignment. The researchers identified five factors that contribute to success in such assignments: job knowledge and motivation, relational skills, flexibility/adaptability, extra-cultural openness, and family situation (spouse’s positive opinion, willingness of spouse to live a broad, and so on; the figure shows some of the specific items that make up each of the five factors).

162 Traits Distinguishing Successful International ExecutivesSCALE Sensitive to Cultural Differences Business Knowledge Courage to Take a Stand Brings Out the Best in People Acts with Integrity Is Insightful Is Committed to Success Takes Risks Uses Feedback Is Culturally Adventurous Seeks Opportunities to Learn Is Open to Criticism Seeks Feedback Is Flexible *Reverse scored SAMPLE ITEM When working with people from other cultures, works hard to understand their perspectives. Has a solid understanding of our products and services. Is willing to take a stand on issues. Has a special talent for dealing with people. Can be depended on to tell the truth regardless of circumstances. Is good at identifying the most important part of a complex problem or issue. Clearly demonstrates commitment to seeing the organization succeed. Takes personal as well as business risks. Has changed as a result of feedback. Enjoys the challenge of working in countries other than his/her own. Takes advantage of opportunities to do new things. Appears brittle—as if criticism might cause him/her to break.* Pursues feedback even when others are reluctant to give in. Doesn’t get so invested in things that she/he cannot change when something doesn’t work.

163 Performance Appraisal of International MangersFive suggestions for improving the expatriate appraisal process: 1. Stipulate the assignment’s difficulty level. For example, being an expatriate manager in China is generally considered more difficult than working in England, and the appraisal should take such difficulty-level differences into account. 2. Weight the evaluation more toward the on-site manager’s appraisal than toward the home-site manager’s distant perceptions of the employee’s performance.

164 Performance Appraisal of International Mangers3. If however (as is usually the case), the home-site manager does the actual written appraisal, have him or her use a former expatriate from the same overseas location to provide background advice during the appraisal process. 4. Modify the normal performance criteria used for that particular position to fit the overseas position and characteristics of that particular locale. 5. Attempt to give the expatriate manager credit for his or her insights into the functioning of the operation and specifically the interdependencies of the domestic and foreign operations.

165 The New Workplace: Sending Women AbroadIn the US, only 6% filled overseas positions compared to 49% domestic One survey found inaccurate stereotypes: Not as internationally mobile Might have a tougher time building teams 77% Effective at building teams Page 473 While the number and proportion of women managers working domestically has climbed in the past few years, the same isn’t true of those assigned abroad. Women filled only about 6% of the overseas international management positions at major companies, according to one estimate, compared with about 49% of domestic U.S. management positions. Women comprise only about 13% of the total expatriate population, according to another survey. Inaccurate stereotypes may account for much of this discrepancy. For example, a new survey (“Passport to Opportunity: U.S. Women in Global Business”) found that respondents believed women aren’t as internationally mobile as men; yet 80% of female expatriates say they’ve never turned down a relocation assignment, compared with 71% of men. Another myth is that women might have a tougher time building relationships with businesspeople overseas; yet 77% of U.S. women in this survey said they were effective at building business relationships with men abroad. Sending Women Managers Abroad 80% Would take foreign assignment

166 Performance Appraisal of International MangersFive suggestions for improving the expatriate appraisal process: 1. Stipulate the assignment’s difficulty level. For example, being an expatriate manager in China is generally considered more difficult than working in England, and the appraisal should take such difficulty-level differences into account. 2. Weight the evaluation more toward the on-site manager’s appraisal than toward the home-site manager’s distant perceptions of the employee’s performance.

167 Performance Appraisal of International Mangers3. If however (as is usually the case), the home-site manager does the actual written appraisal, have him or her use a former expatriate from the same overseas location to provide background advice during the appraisal process. 4. Modify the normal performance criteria used for that particular position to fit the overseas position and characteristics of that particular locale. 5. Attempt to give the expatriate manager credit for his or her insights into the functioning of the operation and specifically the interdependencies of the domestic and foreign operations.

168 Culture Shock! Disorientation upon entering a new cultural environment Normal use of own cultural filter fails interpretation of perceptions communication of intentions All people experience culture shock... Past experience and training can shorten its length

169 Culture Shock: ResponsesGone native (assimilation): accepts the new... rejects own Participator (integration): adapts to the new ... but retains own Tourist (separation): avoids the new... Outcast (marginalization): won’t/can’t adapt... rejects own...

170 Phases Honeymoon Irritation and Hostility (the crisis stage)euphoria, unrealistically positive attitudes towards host country, stay in hotel shields from mundane difficulties, house hunting/school hunting exciting, sightseeing!! Irritation and Hostility (the crisis stage) problems adjusting at work, local clocks don't fit yours, difficulties getting the routine daily tasks done, everything stinks; some never recover

171 Symptoms homesickness boredomwithdrawal (reading is an obsession, focus on home nationals, avoid host nationals) excessive sleep need, compulsive eating and drinking irritability exaggerated cleanliness

172 Symptoms (cont.) marital stress, family tension, conflictstereotyping host nationals hostility towards host nationals loss of ability to work effectively fits of weeping psychosomatic illnesses

173 Phases Gradual Adjustment Biculturalism/Copingcan manage, cope with situation now Biculturalism/Coping ability to function in both cultures, acceptance of local customs and values for what they are (not going native), possible to get by, positive and growth gaining experience

174 Nature of Culture ShockNot a jolt, rather a series of cumulative experiences Cultural differences become focus of attention Foreign ways are quaint no more... they seem inferior to your own

175 What Special Training Do Overseas Candidates Need?Level 1 Level 2 Level 3 Level 4 Impact of cultural differences Understanding attitude formation Factual knowledge about target country Language and adjustment/adaptability skills Page 474 Level 1 training focuses on the impact of cultural differences, and on raising trainees’ awareness of such differences and their impact on business outcomes. Level 2 aims at getting participants to understand how attitudes (both negative and positive) are formed and how they influence behavior. (For example, unfavorable stereotypes may subconsciously influence how a new manager responds to and treats his or her new foreign subordinates.) Level 3 training provides factual knowledge about the target country, while Level 4 provides skill building in areas like language and adjustment and adaptation skills.

176 Four Step Approach to Training Overseas CandidatesLevel 1 training focuses on the impact of cultural differences, and on raising trainees’ awareness of such differences and their impact on business outcomes. Level 2 training aims at getting participants to understand how attitudes (both negative and positive) are formed and how they influence behavior. Level 3 training provides factual knowledge about the target country. Level 4 training provides skill building in areas like language and adjustment and adaptation skills.

177 Cross-Cultural TrainingTraining Time Training Rigor High Months Immersion Approach Assessment Field experience Simulations Sensitivity training Language: “intensive” Affective Approach Weeks Culture assimilator training Role-playing Cases Stress reduction training Cultural Briefings Language: “Moderate” Information Giving Geographic briefings Cultural Briefings Films/Books Interpreters Language: “Survival” Day(s) Low Length of Assignment Weeks Months Years

178 Repatriation of ExpatriatesReturn to one’s home country from an overseas management assignment Reasons for returning Formally agreed-on tour of duty is over Expats want their children educated in the home country Unhappiness with foreign assignment Failure to perform well Readjustment problems Permanent position upon return constitutes a demotion Lack opportunity to use skills learned abroad upon return Salary and benefits may decrease upon return

179 Repatriation Problems50% leave within 2 years Leaving the firm prematurely Mediocre or makeshift jobs Finding former colleagues promoted Reverse culture shock Page 480 Effectively repatriating returning employees is important. Particularly after companies spend hundreds of thousands of dollars helping the person develop international expertise, it’s disconcerting to know that perhaps 50% of returnees leave their companies within two years of coming home. expatriates often fear they’re “out of sight, out of mind” during an extended foreign stay, and such fears are often well founded. Many firms hurriedly assign returning expatriates to mediocre or makeshift jobs. Perhaps more exasperating is discovering that the firm has promoted the expatriate’s former colleagues while he or she was overseas. Even the expatriate’s family may undergo a sort of reverse culture shock, as they face the task of picking up old friendships and starting new schools, and giving up the perks of the over overseas job, like a company car and driver. Consider one employee’s plight. After a 5-year work assignment overseas that entailed much responsibility and a dynamic environment, Scott Fedje returned home to a cubicle, an intellectually non stimulating project, and a whole month to make a single decision. He resigned a few months later.

180 Repatriation Write repatriation agreements Shorten Assignment periodsSeveral steps can be taken to avoid repatriation problems: Write repatriation agreements Shorten Assignment periods Assign a sponsor Provide career counseling Keep communications open Offer financial support Develop reorientation programs Build in return trips

181 Chapter 3-Organizational Cultures and DiversityChapter 3(1): Organisational Culture, Diversity &Multiculturalism Chapter 3(2): Organisational Culture Chapter 3(3): Diversity

182 Chapter 3(1): Organisational Culture, Diversity & Multiculturalism

183 Acknowledging CultureCultural diversity can exist on a national and cross-national level Often, managers assume that culture does not play an important role in shaping practices => Universalistic approach: ‘if it works here, it will work there’ Such approach contributed to high failure rates in expatriate missions and international mergers In order to manage cross-cultural differences, managers need to acknowledge and understand them

184 Diversity-Related ProblemsIncreased ambiguity Increased complexity and confusion Difficulty to converge meanings and Miscommunication Lower cohesiveness Harder to reach agreement Harder to make decisions and agree on specific actions

185 Diversity-Related AdvantagesExpanding meanings and Broader cognitive frame & resources Multiple perspectives Multiple interpretations Richer alternatives & more ideas Increased creativity and problem solving skills Increased flexibility

186 Diversity and Types of OrganizationsOrganizational culture affects the acceptance and impact of diversity in organizations Parochial: Our is the only way Ethnocentric: Our way is best Pluralistic (synergetic): The best is combining our ways and their ways In large companies, different divisions may have different sub-cultures The more complex, unpredictable and global is the business environment of a company, the more competitive advantages cultural diversity has.

187 Nature of Organizational CulturePattern of basic assumptions that are developed by a group as it learns to cope with problems of external adaptation and internal integration and that are taught to new members as the correct way to perceive, think, and feel in relation to these problems An MNC’s organizational culture in one country’s facility may differ sharply from those in other countries

188 Nature of Organizational CultureInteraction Between National and Organizational Cultures National cultural values of employees have a significant impact on organizational performance Cultural values that employees bring to the workplace are not easily changed by the organization Substantial differences may be observed among subsidiaries that cause coordination problems

189 Organizational Cultures in MNCsIntegration of organizational cultures is crucial following mergers and acquisitions Integration process consists of: Establishing a common purpose, goal, and focus Identifying important organizational structures and roles Determining who has authority over resources Identifying the expectations of all involved parties and facilitating communication between the parties

190 Organizational Cultures in MNCs (cont.)Family culture Strong emphasis on hierarchy and person orientation Power-oriented with paternalistic leader Leader looked to for guidance Can catalyze and multiply employees’ energy Reliance on intuition rather than rational knowledge

191 Organizational Cultures in MNCs (cont.)Eiffel tower culture Strong emphasis on hierarchy and task orientation Employees know what to do Coordination from the top Methodic approach to motivating and rewarding people and resolving conflict

192 Organizational Cultures in MNCs (cont.)Guided missile culture Strong emphasis on equality in the workplace and orientation to the task Work typically undertaken by teams or project groups Low priority attached to hierarchical concerns Employs a “cybernetic” structure Culture may change quickly

193 Organizational Cultures in MNCs (cont.)Incubator culture Strong emphasis on equality & personal orientation Organizations are secondary to the fulfillment of individuals Organization is an incubator for self-expression and self-fulfillment Participants have intense emotional commitment to their work

194 Organizational CulturesEquity Fulfillment-oriented culture INCUBATOR Project-oriented culture GUIDED MISSILE Person Emphasis Task Emphasis FAMILY Power-oriented culture EIFFEL TOWER Rule-oriented culture Hierarchy

195 Processes & ImplicationsAttraction-Selection-Attrition framework Where do you advertise for jobs? Who interviews and selects candidates? What type of people is the company (implicitly and explicitly) looking for? Who gets promoted? Mentoring Networking

196 Examples Knowledge workers Medical doctors & nursesUniversity academics

197

198

199 Chapter 3(2) ORGANIZATIONAL CULTUREThis lecture applies cultural concepts to organizations.

200 CULTURE REVIEWED Organizations also have a learned, shared, interrelated set of symbols and patterns of basic assumptions The culture help the organizations cope with problems it faces external adaptation internal integration The introductory case highlights MTV, a Viacom business that has a very distinctive culture. Other firms with distinctive cultures include Disney, Microsoft, Nike, Wal-Mart, Siemens, Toyota, FedEx Your studies of global firms will demonstrate that each has a corporate culture, but these cultures differ from one another; some are strong, some weak. A good example of organizational culture is Walt Disney Corp. (if available show potion of Mickey Mouse Monopoly video—see document for details). As early as 1958, Roy Disney as president said “integration is the key word around here.” Disney has a deeply rooted corporate culture that self-reinforces. For example, Mickey is embedded in everything: buildings, furniture, even the toilet paper at Disney resorts are embossed with a Mickey logo. Everyone is a “cast” member—meaning they are always performing. Bosses are “leads,” and executives dress up as characters from time to time to wander the theme parks. The underground transit systems help to emphasize that everything happens as if by “magic.”

201 CULTURE REVIEWED Culture permeates the organizationCULTURE HELPS ORGANIZATIONS INTEGRATE INTERNALLY (PPS) AND ADAPT/SHAPE EXTERNALITIES (6 GLOBAL ENVIRONMENTS) TO SURVIVE. Culture permeates the organization Through knowledge acquisition Organizational symbols Organizational stories Organizational rites

202 ORGANIZATIONAL KNOWLEDGEExplicit—formalized and widely distributed Implicit—norms or “how we do things around here” Explicit knowledge about culture is usually formalized and widely distributed in printed statements of values, beliefs, or mission.

203 EXAMINE ORGANIZATIONAL SYMBOLSWhat language is in use and where? Who is pictured on annual reports, web pages, or brochures? What colors represent the company; where are they used? What logos are in use? Even a glance at who is pictured on an annual report can tell us much about the organization and what it represents. Organizations sometimes develop their own unique language to convey a particular cultural value. For example, Nike's "Just do it" campaign reflected their preference for action. Organizations also convey messages in verbal and nonverbal forms. For example, logo colors and pictures convey a particular image of the organization.

204 ORGANIZATIONAL STORIES TELL USwhat the employee is supposed to do when in doubt what to do when a high-status person breaks the rules how the little person advances within the organization An example: the 2004 CEO of PepsiCo was featured in an article that reported that on a family outing, the CEO had left a restaurant because they only served Coca Cola. What’s the message this story tells about how people at Pepsi are supposed to view the product?

205 ORGANIZATIONAL RITES REINFORM NORMSRites of degradation dissolve a person’s organizational identity Rites of enhancement recognize accomplishments or enhance power Rites of renewal lubricate social relations Rites of conflict reduction reduces conflict by partitioning it Rites of integration revive common feeling Organizational rites of passage such as a promotion party honor the transition from one role to another. Rites of renewal such as year-end parties help to lubricate social relations, and rites of integration such as team-building exercises or executive retreats may revive or develop a shared sense of organizational purpose.

206 NATIONS TRADITIONALLY SHAPE ORGANIZATIONSBusiness culture

207 BUT INFLUENCES COME FROM MULTIPLE SOURCESProfessional training/groups Family Subgroups, e.g., R&D or accounting

208 INCREASINGLY WE ALSO SEEbusiness influences come not only from domestic influences but also from international and global business activities, e.g., subsidiaries joint ventures and other strategic alliances

209 OFTEN CREATING CULTURE CLASHbetween parent and subsidiary among managers In practices considered “unnatural” to the subsidiary.

210 THUS IN A GLOBAL WORLD, BUSINESSES BECOME CULTURAL CONDUITSSee page 207 of Introduction to Globalization and Business by Barbara Parker What’s the role of business in cultural globalization? Businesses have been cultural conduits and in the past adopted and transmitted norms of their national cultures. As the business world becomes more interdependent worldwide, more businesses go global to become shapers of a hybridized global culture.

211 BUSINESS INFLUENCES CULTURE THROUGHGlobal entertainment and electronic media Global travel Global language Global demographic groups Global elite Global teens Business behaviors Global language of business has been English. According to UNESCO, reported in The Economist Special report Babel runs backwards. January 1, 2005, pp. 62–4. Mandarin Chinese is spoken by about a billion people (only about 100 million speak English), half a billion speak English, a little less than 400 million Speanish, 400 million Hindi, 2.3 million Arabic, 2.2 Bengali, 180 million, Russian, followed by Portuguese, Japanese, German, and French.

212 GLOBAL INFLUENCES OF BUSINESS ON CULTUREMake global businesses more central to Cultural change Cultural concerns And cause them to interact more with social actors such as NGOs and governments

213 Chapter 3(3) DIVERSITY Ideally diversity in the workforce makes global organizations more alert and responsive to their world.

214 Diversity Defined Human diversity Diverse structural configurationsVisible Less or invisible Diverse structural configurations Diverse processes Human diversity is important to organizations when it is important to the individuals who represent it. Visible forms of diversity: gender, race, nationality, age, and physical abilities. Less visible but no less important: religion, marital status, sexual orientation, values, or economic class. Often forgotten is that organizations manage different structural configurations at the same time. In particular, mergers and acquisitions introduce new structural needs; joint ventures differ from wholly owned subsidiaries. Structural diversity results from activities that involve decision-sharing such as strategic alliances and cross-sectoral partnerships. Depending on the types of businesses held in the corporate portfolio, companies may need to structure for diversity in products/services or nations served. Diverse processes—often due to acquisitions and mergers, different HR systems, information systems, etc. Levi Strauss uses the same human resource management principles everywhere. At the same time, due to national differences, Levi does not compensate everyone the same worldwide. The result is diverse compensation systems dependent on national economic practices. In other cases, technological factors may constrain integration of worldwide processes. For example, a weak telecommunications infrastructure in many African nations limits Internet use as a company-wide communication medium. All these forms of diversity challenge seamless integration.

215 Global Organizations Emphasize Inclusive Networks When Theya) reexamine their norms or traditional ways of doing things b) seek and value similarities as well as differences as sources of competitive advantage, and c) train people for skills that enhance a sense of inclusion

216 Diversity InitiativesCommunications Education and Training Employee Involvement CEO speeches Diversity briefings for managers Task forces on diversity Written diversity policy; diversity brochures Awareness training for everyone Interest groups for members of diverse populations Second language publications Diversity skills training Company time provided for diversity planning Reports to the public or to shareholders Multicultural team training Networking groups Press releases Sexual harassment training Career Development Performance and Accountability Mentoring Define behaviors that enhance inclusion Succession planning for diversity Monitor and report on diversity progress Individual development plans Link rewards to achieving diversity objectives Assign people to diverse jobs over a career Develop diversity measures that are both qualitative and quantitative Networking directories

217 Approaches to Managing Human DiversityDiscrimination and fairness Access and legitimacy Learning Discrimination and fairness: this approach assumes that prejudice has kept members of certain groups out of organizations and can be remedied by focusing on equal opportunity, fair treatment, and compliance with legal demands, e.g., EEO in the U.S. Remedies consistent with this paradigm favor assimilation such that newcomers become more like existing employees. Acces and legitimacy: the access and legitimacy paradigm emerged from the competitive business climate of the 1980s and 1990s, relying more on acceptance and valuing of difference than the discrimination and fairness paradigm. This paradigm was motivated by awareness that diversity outside the organization required greater diversity within. Among the limitations of this paradigm is that it accepts diversity without really understanding how diversity can or does change the way work is accomplished. Although boundaries to acceptance can be transcended with this paradigm, boundaries to understanding remain. Learning is a third and emerging paradigm. This perspective not only values diversity, it also argues that differences in perspectives can help organizations learn. Like the fairness paradigm it promotes equal opportunity and like the access paradigm it acknowledges cultural differences, but it transcends both to make learning the glue through which an organization integrates because of its differences, not in spite of them. These perspectives do not stand alone but are instead integrated with other organizational initiatives; people, processes, structures to look like the following slide.

218 Strategic Responses for Managing Diversity and their ImplementationEpisodic Freestanding Systemic Proactive Accommodative Defensive Reactive Strategic responses for managing diversity Low High Pressures for Diversity 1 Deny an assignment to an employee because a client might object to the employee’s nationality, race, gender, age, etc. 2 Choose to risk fines or other costs, rather than engage in equal employment opportunity practices 3 Choose geographic locations for the business which avoid diversity / where the local workforce does not contain protected classes 4 In response to a governmental employment audit, provide a workshop for protected groups on “how to succeed by adapting to fit into the organization” 5 Regular sexual harassment training which focuses on how to avoid legal liability 6 Performance appraisal standards for managers include specific targets / quotas for hiring of protected groups 7 To increase diversity awareness for managers, bring in a speaker to tell them how to value the diversity of their employees 8 Sponsor an annual event that celebrates a protected group, e.g., Special Olympics 9 To ensure equal pay, program the HR computerized management system to annually review and adjust pay differentials between non-protected and protected groups 10 Pilot an employee network conference that engages employees and their managers in reciprocal learning activities 11 Regularly include vendors, suppliers, and customers in the organization’s diversity training offerings to increase their involvement in and contribution to diversity efforts 12 Different business units continually share information about their diversity successes and failures, then adapt and integrate them into their businesses Marginal Strategic Executive priorities for managing diversity

219 Diverse Structures Hierarchical Internal horizontalExport office to functional to divisional to hybrids Internal horizontal Networks, shamrocks, matrix, virtual Interorganizational Joint ventures Strategic alliances

220 Diverse Processes IT—integration depends on infrastructures that varyHR—selection, development, and compensation in different nations and regions Labor practices and conditions Social responsibility and ethics initiatives These are major processes that have been difficult to integrate on a global level; just about every global firm deals with them.

221 Chapter 4 Cross-Cultural Communication and NegotiationChapter 4(2)- Conflict & Negotiation…27

222 Chapter 4(1)- Cross-Cultural Communication

223 Functions of CommunicationCommunication is the exchange of meaning. In organizations, it has several functions: Affecting Behavior – through both formal and informal channels Emotional expression - fulfillment of social needs Information - facilitating decision making

224 The Communication ProcessSource Encoding Channel Decoding Receiver Message Message Message Message Feedback

225 What do you see in the poster?A small class exercise

226 Perception => Attitudes =>Process by which people organize and interpret their sensory impressions in order to give meaning to their environment Perception => Attitudes => Motivation & Behavior People act on their perceptions, not on reality. Because these perceptions can be distorted, people often misinterpret events and activities. When managers want to explain or predict someone’s behavior, they must understand that person’s perception of the world: how he or she organizes and interprets sensory impressions to give meaning to his or her environment. Factors that can shape or distort perception can reside in the perceiver, in the object, or target, being perceived, or in the context in which the perception is made. When an individual attempts to interpret a target, the following characteristics will heavily influence his or her perception: attitudes, personality, motives, interests, past experiences, and expectations. The following also influence perception: characteristics of the target and its relationship to its background; and contextual elements, such as time, location, light, or heat.

227 Attitudes Evaluative statements – favorable or unfavorable –about objects, people, or events; reflect how one feels about something Attitudes are evaluative statements (either favorable or unfavorable) about people, objects, or events. OB focuses on a limited number of job-related attitudes--job satisfaction, job involvement, and organizational commitment. Job satisfaction has received the most attention. Job satisfaction refers to an individual’s general attitude toward his or her job. A person with a high level of job satisfaction holds positive attitudes about the job; a person who is dissatisfied with a job holds negative attitudes about it. The most important determinants of job satisfaction are mentally challenging work, equitable pay and rewards, supportive working conditions, and supportive colleagues. Early views on the satisfaction-productivity relationship asserted that “a happy worker is a productive worker.” But research has shown that if satisfaction does have a positive effect on productivity, it is small. The introduction of moderating variables, however, has improved the relationship. For instance, the relationship is stronger if an employee’s behavior is not constrained by outside factors. According to a comprehensive review of the evidence, it appears that productivity is more likely to lead to satisfaction than the other way around.

228 Perceiver Effects on PerceptionCulture Personality Values & Attitudes Motives Interests Past experiences Expectations

229 Perceptual Shortcuts Assumed Selectivity Similarity Halo EffectThe shortcuts that we use to evaluate others are expeditious, but not foolproof. Because we cannot assimilate everything, what we perceive is selectively chosen depending on our interests, backgrounds, experiences, and attitudes. In assumed similarity, or the “like-me effect,” the observer’s perceptions of others is influenced more by the observer’s own characteristics than by those of the person observed. When we judge someone based on our perception of a group to which he or she belongs, we are stereotyping. When we base our impression of an individual on a single characteristic, such as intelligence or appearance, we are being influenced by the halo effect. Halo Effect Stereotyping

230 Shortcuts to Judging OthersSelectivity - choosing bits of data depending on the interests, background, experience, and attitudes of observer Assumed Similarity - perceptions of others more influenced by what the observer is like or thinks Stereotyping - basing perception on group membership or association Halo Effect - drawing a general impression on the basis of a single characteristic, such as intelligence, sociability, or appearance The shortcuts that we use to evaluate others are expeditious, but not foolproof. Because we cannot assimilate everything, what we perceive is selectively chosen depending on our interests, backgrounds, experiences, and attitudes. In assumed similarity, or the “like-me effect,” the observer’s perceptions of others is influenced more by the observer’s own characteristics than by those of the person observed. When we judge someone based on our perception of a group to which he or she belongs, we are stereotyping. When we base our impression of an individual on a single characteristic, such as intelligence or appearance, we are being influenced by the halo effect.

231 Perception, Attitudes, and PersonalityCulturally based stereotypes Swiss: punctual Germans: task–oriented Americans: energetic People who hold these stereotypes experience surprises when they meet people from these countries who do not fit the stereotypes

232 Perception, Attitudes, and Personality (Cont.)Culturally based stereotypes (cont.) Project aspects of own culture onto people and situations in a different culture Assumes that the new culture mirrors their own Example: Korean manager visiting Sweden assumes all women seated behind desks are secretaries Such behavior would be inappropriate and possibly dysfunctional in Sweden where many women hold management positions

233 Helpful Stereotyping A stereotype can become helpful when it isConsciously held: people are aware it describes a group norm and not individual characteristic Descriptive rather evaluative: how people are, not whether they’re good or bad Accurate: based on data or sufficient experience First best guess: about a group, before acquiring specific information on individuals Dynamic & Flexible: modifiable according to further observation and experience with concrete situations

234 Types of CommunicationVerbal: Oral Face-to-face Distant (phone, video) Written Print Electronic Non-Verbal

235 Overall Communication ProcessVerbal Communication Styles Context Information that surrounds a communication and helps to convey the message High-context societies Messages often are coded and implicit Rely on indirect style

236 Overall Communication ProcessLow-context societies Message is explicit and the speaker says precisely what s/he means Rely on direct style Three degrees of communication quantity Elaborate Exacting Succinct

237 High- vs. Low-Context CulturesHigh Context Low Context Chinese Korean Vietnamese Arab Greek Spanish Italian English French North American Scandinavian German Swiss

238 Overall Communication Process (cont.)Verbal Communication Styles (cont.) Contextual style Focuses on the speaker and relationship of the parties Personal style Focuses on the speaker and the reduction of barriers between the parties

239 Overall Communication Process (cont.)Affective style Characterized by language which requires the listener to carefully note what is being said and to observe how the sender is presenting the message Instrumental style Goal-oriented and focuses on the sender

240 Verbal Styles Used in 10 Select CountriesIndirect vs. Direct Elaborate vs. Succinct Contextual vs. Personal Affective vs. Instrumental Country Australia Direct Exacting Personal Instrumental Canada Direct Exacting Personal Instrumental Denmark Direct Exacting Personal Instrumental Egypt Indirect Elaborate Contextual Affective England Direct Exacting Personal Instrumental Japan Indirect Succinct Contextual Affective Korea Indirect Succinct Contextual Affective Saudi Arabia Indirect Elaborate Contextual Affective Sweden Direct Exacting Personal Instrumental United States Direct Exacting Personal Instrumental

241 Non-verbal CommunicationBody movement (‘Body Language’) adds to, and often complicates, verbal communication Kinesics - Gestures, facial configurations, and other movements of the body Intonations - Change the meaning of the message Facial expression - Characteristics that would never be communicated if you read a transcript of what is said Physical distance - Proper spacing is largely dependent cultural norms

242 Cross-Cultural CommunicationNonverbal communication: a major role across cultures Distance between people North Americans: stand 5 1/2 to 8 feet apart Latin American cultures: people stand much closer Reactions Latin American moves close to the North American North American backs away Latin American might perceive the North American as cold and distant

243 Personal Space Categories for Those In the United StatesIntimate distance 18” Personal distance 18” to 4’ Social distance 4’ to 8’ 8’ to 10’ Public distance

244 Cross-Cultural CommunicationTime orientation Latin Americans view time more casually than North Americans Swiss strongly emphasize promptness in keeping appointments Egyptians usually do not look to the future

245 Cross-Cultural CommunicationTime orientation (cont.) Southeast Asians view the long term as centuries Sioux Indians of the United States do not have words for "time" or "wait" in their native language Potential misunderstandings are large

246 Exercise: Identifying Emotions

247 Emotions & National CultureCultural factors influence what is or is not considered emotionally appropriate Seems to be high agreement of meaning by emotions within cultures What’s acceptable in one culture may seem extremely unusual or dysfunctional in another

248 A Cultural Guide to CommunicationLook for the meaning behind the words Assume differences until similarity is proved Know what you don’t know Emphasize description rather than interpretation or evaluation (of others) Practice empathy & patience Treat your interpretation as a working hypothesis Always: Observe & Listen

249 Chapter 4(2)-Conflict & Negotiation

250 Trust & Culture Individualistic CollectivistPersonal history & experience based Develops through mutual interest (rational) Quicker to trust out-group members Consistency emphasized Collectivist In-group membership based Develops more through emotional bonds Slow trusting out-group members Context is important

251 Conflict Conflict is where one party perceives that another party acting purposefully in a way that upsets the first party or blocks its pursue of goals and interests “Why can't the Jews and the Arabs just sit down together and settle this like good Christians?” - Attributed to Arthur Balfour, 19th century British statesman, Prime Minister, and Foreign Secretary; speaking on the Middle-east Crisis

252 Differences in AttitudesItalian managers: bypassing a manager to reach a subordinate employee is insubordination Swedish and Austrian organizations: decentralized decision making Philippine and Indian organizations: centralized decision making Conclusion: organizations that cross national borders and draw managers from many different countries have high conflict potential.

253 International Aspects of ConflictCultures that emphasize individualism and competition Positively value conflict English–speaking countries, the Netherlands, Italy, Belgium Cultures that emphasize collaboration, cooperation, conformity Negatively value conflict Many Asian and Latin American countries; Portugal, Greece, Turkey

254 International Aspects of ConflictCultural differences imply different functional conflict levels Some cultures favour suppression of conflict with little discussion of people's feelings Felt conflict likely part of some conflict episodes but hidden from public view

255 Conflict (Cont.) Managers from an individualistic country operating in a less individualistic country Acceptable to express feelings during a conflict episode. Suppression of feelings could baffle them Increasing conflict can confuse local people. Almost immediate dysfunctional results

256 Negotiation The process in which two or more parties communicate and exchange goods or services in an attempt to rich a mutually agreeable solution

257 Cultural Differences in NegotiationsNegotiating styles vary among national cultures; for effective cross-cultural negotiation, you need to understand other party’s communication patterns, time orientations, social behavior and idiosyncratic national issues.

258 Successful Negotiators’ CharacteristicsUS Japanese Taiwanese Brazilian Preparation & planning skill Dedication to job Persistence & determination Thinking under pressure Perceive & exploit power Win respect & confidence Judgment & intelligence Verbally expressive Integrity Product knowledge Demonstrate listening skills Interesting Broad perspective Competitive

259 Cultural Differences in NegotiationsCultural context significantly influences: History & identity in relation to conflict Time frame (short/long; deadlines) Emphasis on rationality/emotion/ideals The amount and type of preparation for bargaining Participants: few essential or ‘the more the merrier’; young professional or respectable elder The relative emphasis on task versus interpersonal relationships and formal vs. informal mechanisms (e.g., lawyers)

260 Differences in NegotiationsWhere the negotiation should be conducted (business/leisure) and emphasis on entertainment Communication patterns (verbal/nonverbal); direct vs. non-direct rejection The tactics used: Extent of bargaining Initial offers—extreme or moderate Nonverbal behavior

261 Verbal Tactics (per ½ hour session)Behavior US Brazilian Japanese Promise 8 3 7 Normative 2 1 4 Commitment 13 15 Self-Disclosure 36 39 34 Command 6 14 “No’s” 9 83.4 5.7 Profit level 57.3 75.2 61.5 Initial concessions 7.1 9.4 6.5

262 Nonverbal Tactics Behavior US Brazilian Japanese 3.5 5.5 10.3 28.6Silent periods (per 30 min.) 3.5 5.5 Conversational overlaps (per 10 min.) 10.3 28.6 12.6 Facial gazing (minutes per 10 min.) 3.3 5.2 1.3 Touching (per 30 min.) 4.7

263 Chapter 5 Link Layer and LANsA note on the use of these ppt slides: We’re making these slides freely available to all (faculty, students, readers). They’re in PowerPoint form so you can add, modify, and delete slides (including this one) and slide content to suit your needs. They obviously represent a lot of work on our part. In return for use, we only ask the following: If you use these slides (e.g., in a class) in substantially unaltered form, that you mention their source (after all, we’d like people to use our book!) If you post any slides in substantially unaltered form on a www site, that you note that they are adapted from (or perhaps identical to) our slides, and note our copyright of this material. Thanks and enjoy! JFK/KWR All material copyright J.F Kurose and K.W. Ross, All Rights Reserved Computer Networking: A Top Down Approach 4th edition. Jim Kurose, Keith Ross Addison-Wesley, July 2007. 5: DataLink Layer

264 Chapter 5: The Data Link LayerOur goals: understand principles behind data link layer services: error detection, correction sharing a broadcast channel: multiple access link layer addressing reliable data transfer, flow control: done! instantiation and implementation of various link layer technologies 5: DataLink Layer

265 Link Layer 5.1 Introduction and services5.2 Error detection and correction 5.3Multiple access protocols 5.4 Link-Layer Addressing 5.5 Ethernet and other data link layers 5.6 Hubs and switches 5.7 PPP 5.8 Link Virtualization: ATM and MPLS 5: DataLink Layer

266 Link Layer: IntroductionSome terminology: hosts and routers are nodes communication channels that connect adjacent nodes along communication path are links wired links wireless links LANs layer-2 packet is a frame, encapsulates datagram data-link layer has responsibility of transferring datagram from one node to adjacent node over a link 5: DataLink Layer

267 Adaptors Communicatingdatagram link layer protocol rcving node sending node frame frame adapter adapter link and physical layers implemented in adaptor/NIC (Network Interface Card) RAM, DSP chips, host bus interface, and link interface Ethernet card, PCMCIA card, card sending side: encapsulates datagram in a frame adds error checking bits, rdt, flow control, etc. receiving side looks for errors, rdt, flow control, etc extracts datagram, passes to upper layer at receiving side datagram transferred by different link protocols over different links: e.g., Ethernet on first link, frame relay on intermediate links, on last link 5: DataLink Layer

268 Protocol stack pictureapplication transport network link physical network link physical M H t n l data link protocol H l H t n M frame phys. link adapter card 5: DataLink Layer

269 Host adaptor 5: DataLink Layer controller physical transmission cpumemory host bus (e.g., PCI) network adapter card host schematic application transport network link 5: DataLink Layer

270 Link Layer Functions Flow Controlpacing between adjacent sending and receiving nodes Reliable delivery between adjacent nodes we learned how to do this already (chapter 3)! seldom used on low bit error link (i.e. fiber, twisted pair) wireless links: high error rates Eschew end-to-end principle for performance Security Demux to upper protocol Framing encapsulate datagram into frame, adding header, trailer 5: DataLink Layer

271 Link Layer Functions (more)Error Detection errors caused by signal attenuation, noise. receiver detects presence of errors: signals sender for retransmission or drops frame Error Correction receiver identifies and corrects bit error(s) without resorting to retransmission Medium access and quality of service channel access if shared medium Addressing “MAC” addresses used in frame headers to identify source, dest (different from IP address) 5: DataLink Layer

272 Flow control Pacing between sender and receiverSender prevented from overrunning receiver Ready-To-Send, Clear-To-Send signalling 5: DataLink Layer

273 Reliable delivery Reliability at the link layerHandled in a similar manner to transport protocols ARQ, Stop-and-wait, Go-back-N, Selective Repeat When and why should this be used? Rarely done over twisted-pair or fiber optic links Usually done over lossy links for performance improvement (versus correctness) 5: DataLink Layer

274 Security Mainly for broadcast data-link layersEncrypt payload of higher layers Hide IP source/destination from eavesdroppers Important for wireless LANs especially Parking lot attacks with b WEP, WPA If time permits, security will be covered at the end of the course…. 5: DataLink Layer

275 Demux to upper protocolProtocol type specification interfaces to network layer Data-link layer can support any number of network layers Type field in data-link header specifies network layer of packet Each data-link layer defines its own protocol type numbering for network layer IP is one of many network layers 5: DataLink Layer

276 Demux to upper protocol Some Ethernet protocol types 0800 DOD Internet Protocol (IP) 0806 Address Resolution Protocol (ARP) 8037 IPX (Novell Netware) 80D5 IBM SNA Services 809B EtherTalk (AppleTalk over Ethernet) 5: DataLink Layer

277 Framing Data encapsulation for transmission over physical linkData embedded within a link-layer frame before transmission Data-link header and/or trailer added Physical addresses used in frame headers to identify source and destination (not IP) 5: DataLink Layer

278 Fixed length framing Length delimited Beginning of frame has lengthSingle corrupt length can cause problems Must have start of frame character to resynchronize Resynchronization can fail if start of frame character is inside packets as well Draw on board 5: DataLink Layer

279 Variable length framingByte stuffing Special start of frame byte (e.g. 0xFF) Special escape byte value (e.g. 0xFE) Values actually in text are replaced (e.g. 0xFF by 0xFEFF and 0xFE by 0xFEFE) Worst case – can double the size of frame Bit stuffing Special bit sequence (0x ) 0 bit stuffed after any sequence 5: DataLink Layer

280 Clock-Based Framing Used by SONET Fixed size frames (810 bytes)Look for start of frame marker that appears every 810 bytes Will eventually sync up 5: DataLink Layer

281 Link Layer 5.1 Introduction and services5.2 Error detection and correction 5.3Multiple access protocols 5.4 Link-Layer Addressing 5.5 Ethernet and other data link layers 5.6 Hubs and switches 5.7 PPP 5.8 Link Virtualization: ATM 5: DataLink Layer

282 Error detection/correctionErrors caused by signal attenuation, noise. Receiver detects presence of errors Possible actions Signal sender for retransmission Drops frame Correct bit errors if possible and continue 5: DataLink Layer

283 Error Detection EDC= Error Detection and Correction bits (redundancy)D = Data protected by error checking, may include header fields Error detection not 100% reliable! protocol may miss some errors, but rarely larger EDC field yields better detection and correction 5: DataLink Layer

284 Parity Checking Two Dimensional Bit Parity: Single Bit Parity:Detect single bit errors Two Dimensional Bit Parity: Detect and correct single bit errors 5: DataLink Layer

285 Cyclic Redundancy Check (CRC)Polynomial code Treat data bits as coefficients of n-bit polynomial Choose r+1 bit generator polynomial G G well known – chosen in advance Add r bits to packet so that message is divisible by G At receiver, divide payload by generator polynomial If result not zero, error detected Better loss detection properties than checksums All single bit errors, all double bit errors, all odd-numbered errors, burst errors less than r Widely used in practice (802.11, WiFi, ATM, SCTP) 5: DataLink Layer

286 Cyclic Redundancy Check (CRC)Calculate code using modulo 2 division of data by generator polynomial Subtraction equivalent to XOR Weak definition of magnitude X >= Y iff position of highest 1 bit of X is the same or greater than the highest 1 bit of Y Record remainder “R” after division and attach “R” after data Result divisible by generator polynomial 5: DataLink Layer

287 Cyclic Redundancy Check (CRC)5: DataLink Layer

288 CRC example Data: 101110 Generator Polynomial: x3 + 1 (1001) Send: 5: DataLink Layer

289 CRC example Data: 10000 Generator Polynomial: x2 + 1 (101) Send: G 5: DataLink Layer

290 CRC example Data: 10000 Generator Polynomial: x2 + 1 (101) Send: G 101 101 010 000 100 01 D R 5: DataLink Layer

291 Cyclic Redundancy Check (CRC)CRC-16 implementation Shift register and XOR gates 5: DataLink Layer

292 CRC polynomials CRC-16 = x16 + x15 + x2+ 1 (used in HDLC)CRC-CCITT = x16 + x12 + x5 + 1 CRC-32 = x32 + x26 + x23 + x22 + x16 + x12 + x11 + x10 + x8 + x7 + x5 + x4 + x2 + x + 1 (used in Ethernet) 5: DataLink Layer

293 Forward error correctionFEC Use error correcting codes to repair losses Add redundant information which allows receiver to correct bit errors See information and coding theory work. 5: DataLink Layer

294 Link Layer 5.1 Introduction and services5.2 Error detection and correction 5.3Multiple access protocols 5.4 Link-Layer Addressing 5.5 Ethernet and other data link layers 5.6 Hubs and switches 5.7 PPP 5.8 Link Virtualization: ATM 5: DataLink Layer

295 Multiple Access Links and ProtocolsTwo types of “links”: point-to-point PPP for dial-up access point-to-point link between Ethernet switch and host broadcast (shared wire or medium) old-fashioned Ethernet upstream HFC (cable) wireless LAN humans at a cocktail party (shared air, acoustical) shared wire (e.g., cabled Ethernet) shared RF (e.g., WiFi) shared RF (satellite) 5: DataLink Layer

296 Multiple access problemPoint-to-point link and switched media no problem Broadcast links? Network arbitration Give everyone a fixed time/freq slot? Ok for fixed bandwidth (e.g., voice) What if traffic is bursty? Centralized arbiter Ex: cell phone base station Single point of failure Distributed arbitration Aloha/Ethernet Humans use multiple access protocols all the time 5: DataLink Layer

297 Multiple access protocolssingle shared communication channel two or more simultaneous transmissions by nodes: interference only one node can send successfully at a time multiple access protocol: distributed algorithm that determines how stations share channel, i.e., determine when station can transmit communication about channel sharing uses channel itself! what to look for in multiple access protocols: synchronous or asynchronous amount of information needed about other stations robustness (e.g., to channel errors) performance 5: DataLink Layer

298 Ideal Multiple Access ProtocolBroadcast channel of rate R bps 1. Efficient: When one node wants to transmit, it can send at rate R. 2. Fair: When M nodes want to transmit, each can send at average rate R/M 3. Fully decentralized: no special node to coordinate transmissions no synchronization of clocks, slots 4. Simple 5: DataLink Layer

299 MAC Protocols: a taxonomyThree broad classes: Channel Partitioning divide channel into smaller “pieces” (time slots, frequency, code) allocate piece to node for exclusive use Random Access channel not divided, allow collisions “recover” from collisions “Taking turns” tightly coordinate shared access to avoid collisions Nodes take turns, but nodes with more to send can take longer turns 5: DataLink Layer

300 Channel Partitioning MAC protocols: TDMATDMA: time division multiple access channel divided into N time slots, one per user access to channel in "rounds" inefficient with low duty cycle users and at light load each station gets fixed length slot (length = pkt trans time) in each round unused slots go idle example: 6-station LAN, 1,3,4 have pkt, slots 2,5,6 idle 6-slot frame 1 3 4 1 3 4 5: DataLink Layer

301 Channel Partitioning MAC protocols: FDMAFDMA: frequency division multiple access channel spectrum divided into frequency bands each station assigned fixed frequency band unused transmission time in frequency bands go idle example: 6-station LAN, 1,3,4 have pkt, frequency bands 2,5,6 idle time frequency bands FDM cable 5: DataLink Layer

302 Channel Partitioning MAC protocolsCDMA (Code Division Multiple Access) unique “code” assigned to each user; ie, code set partitioning used mostly in wireless broadcast channels (cellular, satellite,etc) each user has own “chipping” sequence (ie, code) to encode data encoded signal = (original data) X (chipping sequence) decoding: inner-product of encoded signal and chipping sequence allows multiple users to “coexist” and transmit simultaneously with minimal interference (if codes are “orthogonal”) 5: DataLink Layer

303 Channel Partitioning MAC protocolsCDMA Encode/Decode 5: DataLink Layer

304 Channel Partitioning MAC protocolsCDMA: two sender interference 5: DataLink Layer

305 Random Access ProtocolsWhen node has packet to send transmit at full channel data rate R. no a priori coordination among nodes two or more transmitting nodes ➜ “collision”, To avoid deterministic collisions: randomize random access MAC protocol specifies: how to detect collisions how to recover from collisions (e.g., via delayed retransmissions) “Asynchronous” TDMA Examples of random access MAC protocols: slotted ALOHA ALOHA CSMA, CSMA/CD, CSMA/CA 5: DataLink Layer

306 Slotted ALOHA Assumptions all frames same sizetime is divided into equal size slots, time to transmit 1 frame nodes start to transmit frames only at beginning of slots nodes are synchronized if 2 or more nodes transmit in slot, all nodes detect collision Operation when node obtains fresh frame, it transmits in next slot no collision, node can send new frame in next slot if collision, node retransmits frame in each subsequent slot with prob. p until success 5: DataLink Layer

307 Slotted ALOHA Pros single active node can continuously transmit at full rate of channel highly decentralized: only slots in nodes need to be in sync simple Cons collisions, wasting slots idle slots nodes may be able to detect collision in less than time to transmit packet clock synchronization 5: DataLink Layer

308 Slotted Aloha efficiencyEfficiency is the long-run fraction of successful slots when there are many nodes, each with many frames to send For max efficiency with N nodes, find p* that maximizes Np(1-p)N-1 For many nodes, take limit of Np*(1-p*)N-1 as N goes to infinity, gives 1/e = .37 Suppose N nodes with many frames to send, each transmit in slot with probability p prob that node 1 has success in a slot = p(1-p)N-1 prob that any node has a success = Np(1-p)N-1 At best: channel used for useful transmissions 37% of time! 5: DataLink Layer

309 Pure (unslotted) ALOHAunslotted Aloha: simpler, no synchronization when frame arrives Send without awaiting for beginning of slot collision probability increases: frame sent at t0 collides with other frames sent in [t0-1,t0+1] 5: DataLink Layer

310 protocol constrains effective channel throughput!Pure Aloha efficiency P(success by given node) = P(node transmits) . P(no other node transmits in [p0-1,p0] . P(no other node transmits in [p0,p0+1] = p . (1-p)(N-1) . (1-p) (N-1) P(success by any of N nodes) = N p . (1-p) (N-1). (1-p) (N-1) … choosing optimum p as n -> infty = 1/(2e) = .18 G = offered load = Np 0.5 1.0 1.5 2.0 0.1 0.2 0.3 0.4 Pure Aloha Slotted Aloha S = throughput = “goodput” (success rate) protocol constrains effective channel throughput! 5: DataLink Layer

311 CSMA (Carrier Sense Multiple Access)Human analogy: don’t interrupt others! Listen before transmitting CSMA algorithm If channel sensed idle: transmit entire frame If channel sensed busy, defer transmission Persistent CSMA: retry immediately with probability p when channel becomes idle Non-persistent CSMA: retry after random interval 5: DataLink Layer

312 CSMA collisions collisions can still occur: collision: note:spatial layout of nodes collisions can still occur: propagation delay means two nodes may not hear each other’s transmission collision: entire packet transmission time wasted note: role of distance & propagation delay in determining collision probability 5: DataLink Layer

313 CSMA/CD (Collision Detection)Human analogy: the polite conversationalist CSMA/CD algorithm Carrier sensing, deferral as in CSMA Attempt to detect collisions while sending Abort colliding transmissions as soon as possible to reduce channel wastage Collision detection: Easy in wired LANs: measure signal strengths, compare transmitted, received signals Collisions detected within short time 5: DataLink Layer

314 CSMA/CD collision detection5: DataLink Layer

315 CSMA/CD problems Can CSMA/CD work over wireless LANs?Collision detection difficult in wireless LANs: receiver shut off while transmitting Hidden terminal problem 5: DataLink Layer

316 Hidden Terminal effectA, C cannot hear each other obstacles, signal attenuation Neither A nor C can tell if they collide at B 5: DataLink Layer

317 CSMA/CA: CSMA w/ collision avoidanceUse base CSMA Add acknowledgements Receiver acknowledges receipt of data Avoids hidden terminal problem Avoid collisions explicitly via channel reservation Sender sends “request-to-send” (RTS) messages Transmitted without reservation using CSMA with ACKs Receiver sends “clear-to-send” (CTS) messages Sender sends data packet using reservation Explicitly indicates length of so others know how long to back off Used in wireless LAN networks 5: DataLink Layer

318 “Taking Turns” MAC protocolsRecall, channel partitioning MAC protocols: share channel efficiently and fairly at high load inefficient at low load: delay in channel access, 1/N bandwidth allocated even if only 1 active node! Random access MAC protocols efficient at low load: single node can fully utilize channel high load: collision overhead “taking turns” protocols look for best of both worlds! 5: DataLink Layer

319 “Taking Turns” MAC protocolsPolling: master node “invites” slave nodes to transmit in turn RTS, CTS messages typically used with “dumb” slave devices concerns: polling overhead latency single point of failure (master) data poll master data slaves 5: DataLink Layer

320 “Taking Turns” MAC protocolsToken passing: control token passed from one node to next sequentially. token message concerns: token overhead latency single point of failure (token) T (nothing to send) T data 5: DataLink Layer

321 Taking-turns protocolsDistributed Polling: time divided into slots begins with N short reservation slots reservation slot time equal to channel end-end propagation delay station with message to send posts reservation reservation seen by all stations after reservation slots, message transmissions ordered by known priority 5: DataLink Layer

322 Summary of MAC protocolsWhat do you do with a shared media? Channel Partitioning Time Division Frequency Division Code Division Random partitioning (dynamic), ALOHA, S-ALOHA, CSMA, CSMA/CD carrier sensing: easy in some technologies (wire), hard in others (wireless) CSMA/CD used in Ethernet CSMA/CA used in Taking Turns polling from a central site, token passing Bluetooth, FDDI, IBM Token Ring 5: DataLink Layer

323 Link Layer 5.1 Introduction and services5.2 Error detection and correction 5.3Multiple access protocols 5.4 Link-Layer Addressing 5.5 Ethernet and other data link layers 5.6 Hubs and switches 5.7 PPP 5.8 Link Virtualization: ATM 5: DataLink Layer

324 MAC Addresses MAC/LAN/physical/Ethernet address:used to get frame from one interface to another physically-connected interface (same network) Globally unique 48 bit address (for most LANs) burned in the adapter ROM ifconfig –a Administered by IEEE manufacturer buys portion of MAC address space to assure uniqueness 5: DataLink Layer

325 LAN Addresses Broadcast address = FF-FF-FF-FF-FF-FF LAN = adapterEach adapter on LAN has unique LAN address 1A-2F-BB AD Broadcast address = FF-FF-FF-FF-FF-FF LAN (wired or wireless) = adapter 71-65-F7-2B-08-53 58-23-D7-FA-20-B0 0C-C4-11-6F-E3-98 5: DataLink Layer

326 MAC vs IP addressing MAC address IP addressesFlat (not hierarchical) Like Social Security Numbers Does not change when machine is moved (portable) IP addresses Hierarchically organized Like postal address Depends on IP subnet that node is attached to Must change when machine is moved (not portable) Why have separate IP and hardware addresses? Assign adapters an IP address Hardware only works for IP (no IPX, DECNET) Use hardware address as network address No route aggregation 5: DataLink Layer

327 ARP: Address Resolution ProtocolQuestion: how to determine MAC address of B given B’s IP address? ARP Broadcast interest in B’s MAC address B responds with its MAC address Keep track of mappings in ARP table IP/MAC address mappings for LAN nodes < IP address; MAC address; TTL> TTL (Time To Live) Soft state 1A-2F-BB AD LAN 71-65-F7-2B-08-53 58-23-D7-FA-20-B0 0C-C4-11-6F-E3-98 5: DataLink Layer

328 ARP protocol: Same LAN (network)A knows B’s IP address and wants to send datagram to B, and B’s MAC address not in A’s ARP table. A broadcasts ARP query packet, containing B's IP address Dest MAC address = FF-FF-FF-FF-FF-FF all machines on LAN receive ARP query B receives ARP packet, replies to A with its (B's) MAC address frame sent to A’s MAC address (unicast) A caches (saves) IP-to-MAC address pair in its ARP table until information becomes old (times out) soft state: information that times out (goes away) unless refreshed ARP is “plug-and-play”: nodes create their ARP tables without intervention from net administrator arp –a /proc/net/arp 5: DataLink Layer

329 Routing to another LAN walkthrough: send datagram from A to B via Rassume A knows B’s IP address Two ARP tables in router R, one for each IP network (LAN) In routing table at source Host, default route A creates datagram with source A, destination B A R B 5: DataLink Layer

330 A R B A checks route table to find B is not on its networkA uses ARP to get R’s MAC address (ARP for ) A creates link-layer frame with R's MAC address as dest, frame contains A-to-B IP datagram A’s adapter sends frame R’s adapter receives frame R removes IP datagram from Ethernet frame, sees its destined to B R uses ARP to get B’s MAC address R creates frame containing A-to-B IP datagram sends to B A R B 5: DataLink Layer

331 DHCP Q: How does host get an IP address on subnet?hard-coded by system admin in a file Wintel: control-panel->network->configuration->tcp/ip->properties UNIX: /etc/rc.config DHCP: Dynamic Host Configuration Protocol: dynamically get address from server “plug-and-play” Given a hardware address, give me the IP address Predecessors: RARP, BOOTP Opposite of ARP (given IP address, give me MAC address) 5: DataLink Layer

332 DHCP: Dynamic Host Configuration ProtocolGoal: allow host to dynamically obtain its IP address from network server when it joins network Allows reuse of addresses (only hold address while connected and “on”) Support for mobile users who want to join network Can renew its lease on address in use DHCP overview: host broadcasts “DHCP discover” msg DHCP server responds with “DHCP offer” msg host requests IP address: “DHCP request” msg DHCP server sends address: “DHCP ack” msg 5: DataLink Layer

333 DHCP client-server scenario server B arriving DHCP client needs address in this ( /24) network E 5: DataLink Layer

334 DHCP client-server scenarioDHCP server: arriving client DHCP discover src : , 68 dest.: ,67 yiaddr: transaction ID: 654 DHCP offer src: , 67 dest: , 68 yiaddrr: transaction ID: 654 Lifetime: 3600 secs DHCP request src: , 68 dest:: , 67 yiaddrr: transaction ID: 655 Lifetime: 3600 secs time DHCP ACK src: , 67 dest: , 68 yiaddrr: transaction ID: 655 Lifetime: 3600 secs 5: DataLink Layer

335 Link Layer 5.1 Introduction and services5.2 Error detection and correction 5.3Multiple access protocols 5.4 Link-Layer Addressing 5.5 Ethernet and other data link layers 5.6 Hubs and switches 5.7 PPP 5.8 Link Virtualization: ATM 5: DataLink Layer

336 Specific data-link layersEthernet (802.3) Token Ring (802.5) WiFi (802.11) Frame relay Special link layers covered later (PPP, ATM) 5: DataLink Layer

337 Ethernet's implementation of data-link layerFraming (special pre-amble within frame) Physical addressing (6 byte hardware addresses) Demux to upper protocol (type field in header) Flow control (none) Error detection and correction (CRC-32) Reliable delivery (none) Security (none) Media access and quality of service (CSMA/CD with adaptive, randomized wait) Digital to analog conversion (Manchester encoding) 5: DataLink Layer

338 Ethernet Metcalfe’s Ethernet sketch “dominant” wired LAN technology:First practical local area network, built at Xerox PARC in 70’s first widely used LAN technology Simpler, cheaper than token LANs and ATM cheap: $3 for 100Mbs NIC Metcalfe’s Ethernet sketch 5: DataLink Layer

339 Ethernet topologies bus: coaxial cable star Flexible topologiesBus topology popular through mid 90s all nodes in same collision domain requires the use of CSMA/CD Star topology today active switch in center each “spoke” runs a (separate) Ethernet protocol (nodes do not collide with each other) switch bus: coaxial cable star 5: DataLink Layer

340 Ethernet Frame StructureSending adapter encapsulates IP datagram (or other network layer protocol packet) in Ethernet frame Preamble: 7 bytes with pattern followed by one byte with pattern used to synchronize receiver, sender clock rates 5: DataLink Layer

341 Ethernet Frame Structure (more)Addresses: 6 bytes Globally unique, allocated to manufacturers if adapter receives frame with matching destination address, or with broadcast address (eg ARP packet), it passes data in frame to net-layer protocol otherwise, adapter discards frame Type: indicates the higher layer protocol mostly IP but others include Novell IPX and AppleTalk Data – 46 to 1500 bytes CRC: 4 bytes checked at receiver, if error is detected, frame is dropped CRC-32 (x32+x26+x23+x22+x16+x12+x11+x10+x8+x7+x5+x4+x2+x+1) 5: DataLink Layer

342 Unreliable, connectionless serviceConnectionless: No handshaking between sending and receiving adapter. Unreliable: receiving adapter doesn’t send acks or nacks to sending adapter stream of datagrams passed to network layer can have gaps gaps will be filled if app is using TCP otherwise, app will see the gaps 5: DataLink Layer

343 Ethernet CSMA/CD algorithm1. Adaptor receives datagram from net layer & creates frame 2. Carrier sensing: If adapter senses channel idle, it starts to transmit frame. If it senses channel busy, waits until channel idle and then transmits 3. If adapter transmits entire frame without detecting another transmission, the adapter is done with frame ! 4. Collision detection: If adapter detects another transmission while transmitting, aborts and sends jam signal (make sure all adapters see collision: 48 bits) 5. Random access: After aborting, adapter enters exponential backoff before returning to Step 2 after m th collision, choose K randomly out of {0,1,2,…2m-1}. Wait K*512 bit times first collision: choose K from {0,1}; delay is K· 512 bit transmission times after second collision: choose K from {0,1,2,3}… after ten collisions, choose K from {0,1,2,3,4,…,1023} 5: DataLink Layer

344 Exponential backoff calculationGoal: adapt retransmission attempts to estimated current load heavy load: random wait will be longer Deterministic delay after collision Collision will occur again in lockstep Random delay with fixed mean Few senders  needless waiting Too many senders  too many collisions Exponentially increasing random delay Infer senders from # of collisions More senders  increase wait time See/interact with Java applet on AWL Web site: highly recommended ! 5: DataLink Layer

345 General Ethernet CSMA/CDPacket? No Sense Carrier Send Detect Collision attempts < 16 Yes Discard Packet b=CalcBackoff(); wait(b); attempts++; attempts == 16 5: DataLink Layer

346 Ethernet CSMA/CD and Packet SizeWhat if two people sent really small packets How do you find collision? Must have a minimum packet size Min packet length > 2x max prop delay If A, B are at opposite sides of link, and B starts one link prop delay after A 5: DataLink Layer

347 Propagation delay & packet sizePropagation delay determines min. packet size to prevent undetected collisions Modern 10Mb Ethernet Segment length to support? 500m maximum segment length Can add repeaters up to a maximum 5 segments (2500m) Propagation delay for maximum segment c in cable = 60% * c in vacuum = 1.8 x 10^8 m/s ~ 12.5us one-way delay Add repeater and tranceiver delay To be safe IEEE specifies a 512 “bit-time” slot for Ethernet = 51.2us 512 bits = 64 bytes (minimum data payload = 46 bytes) 5: DataLink Layer

348 Minimum packet size What about scaling? 100Mbit, 1Gbit...Make network smaller? Solution for 100BaseT Make min pkt size larger? 1Gbps = 512ns 512ns * 1.8 * 10^8 = 92meters Gigabit ethernet uses collision extension for small pkts 5: DataLink Layer

349 Ethernet Problems Ethernet unstable at high loadsPeak throughput worse with More hosts – more collisions needed to identify single sender Smaller packet sizes – more frequent arbitration Longer links – collisions take longer to observe, more wasted bandwidth 5: DataLink Layer

350 Token Rings Packets broadcast around ringToken “right to send” rotates around ring Fair, real-time bandwidth allocation Every host holds token for limited time Higher latency when only one sender 5: DataLink Layer

351 Token Passing: IEEE802.5 standard4 Mbps max token holding time: 10 ms (limits frame length) SD, ED mark start, end of packet AC: access control byte: token bit: value 0 means token can be seized, value 1 means data follows FC priority bits: priority of packet reservation bits: station can write these bits to prevent stations with lower priority packet from seizing token after token becomes free 5: DataLink Layer

352 Why Did Ethernet Win? Better failure modesToken rings – network unusable Ethernet – node detached Good performance in common case Volume  lower cost  higher volume …. Adaptable To higher bandwidths (vs. FDDI) To switching (vs. ATM) Completely distributed, easy to maintain/administer Easy incremental deployment Cheap cabling, etc 5: DataLink Layer

353 IEEE 802.11 Wireless LAN Untethered (often mobile) networkingIEEE standard: Defines specific implementations of data-link functions Framing, error detection, MAC, etc. Unlicensed frequency spectrum: 900Mhz, 2.4Ghz 5: DataLink Layer

354 IEEE Ad-hoc mode Ad hoc network: stations can dynamically form network without AP Applications: “laptop” meeting in conference room, car interconnection of “personal” devices battlefield IETF MANET (Mobile Ad hoc Networks) working group 5: DataLink Layer

355 IEEE 802.11 Infrastructure modeTypically used with access point (base station) Several communication methods supported CSMA (with explicit ACK to indicate collision) CSMA/CA: reservations Polling from AP 5: DataLink Layer

356 IEEE 802.11 MAC Protocol: CSMACSMA sender - if sense channel idle for DIFS sec. then transmit entire frame (no collision detection) -if sense channel busy then backoff (random, exponential) CSMA receiver -if received OK return ACK after SIFS SIFS < DIFS allows acks to grab channel with higher priority CSMA others NAV: Network Allocation Vector frame has transmission time field others (hearing data) defer access for NAV time units 5: DataLink Layer

357 IEEE 802.11 MAC Protocol CSMA/CASame as previous mode but with explicit channel reservation Send short reservation messages via CSMA to reserve channel Sender RTS (request to send), Receiver CTS (clear to send) CTS notifies all hidden stations of sender's reservation Short messages so that collision less likely and of short duration Send data unobstructed on reserved channel End result similar to CSMA/CD 5: DataLink Layer

358 Link Layer 5.1 Introduction and services5.2 Error detection and correction 5.3Multiple access protocols 5.4 Link-Layer Addressing 5.5 Ethernet and other data link layers 5.6 Interconnections: Hubs and switches 5.7 PPP 5.8 Link Virtualization: ATM 5: DataLink Layer

359 Link-layer devices Q: Why not just one big LAN?limited aggregate bandwidth limited length: electrical limitations large “collision domain” (can collide with many stations) access delay (eg token passing delay) 5: DataLink Layer

360 Hubs Hubs are essentially physical-layer, multi-port repeaters:bits coming from one link go out all other links at the same rate addresses electrical limitations no frame buffering no CSMA/CD at hub: adapters detect collisions all nodes connected to hub can collide with one another twisted pair hub 5: DataLink Layer

361 Hubs (more) Hubs do not isolate collision domains: node may collide with any node residing at any segment in LAN Hub Advantages: simple, inexpensive device extends maximum distance between node pairs 5: DataLink Layer

362 Interconnecting with hubsBackbone hub interconnects LAN segments But individual segment collision domains become one large collision domain Single collision domain results in no increase in max throughput Simultaneous transfers between A to A’ and B to B’ collide Multi-tier throughput same as single segment throughput Can’t interconnect 10BaseT & 100BaseT hub hub A hub hub B A’ B’ 5: DataLink Layer

363 Switches Link Layer deviceSmarter than hubs Actively stores and forwards Ethernet frames Examines frame header and selectively forwards frame based on destination MAC address Two-port switch known as a “bridge” Switches known as “multi-port” bridges A switch isolates collision domains since it buffers frames Uses CSMA/CD to access individual network segments to transmit frames Transparent to hosts Plug-and-play, self-learning (do not need to be configured) 5: DataLink Layer

364 Switches: multiple simultaneous transmissionsHosts have dedicated direct connection to switch Ethernet protocol and frame used, but… No collisions Each link is its own collision domain Full duplex operation Switch buffers frames Much greater aggregate bandwidth Data backplane of switches typically large to support simultaneous transfers amongst ports Switching: A-to-A’ and B-to-B’ simultaneously, no collisions A C’ B switch C B’ A’ 5: DataLink Layer

365 Switches (more) Switch advantages:Isolates collision domains resulting in higher total max throughput Can connect different type Ethernet since it is a store and forward device Transparent: no need for any change to hosts LAN adapters 5: DataLink Layer

366 Switch operation switch 1 3 2 hubHow do determine onto which LAN segment to forward frame? Looks like a routing problem... 5: DataLink Layer

367 Self learning ApproachMonitor traffic to build a cache (switch table) of which nodes are downstream of which ports (MAC Address, Interface, Time Stamp) learns which hosts can be reached through which interfaces Selectively forward frames based on cache entries Flood network for frames with unknown (MAC) destinations 5: DataLink Layer

368 Switch algorithm When frame received:1. record link associated with sending host 2. index switch table using MAC dest address 3. if entry found for destination then { if dest on segment from which frame arrived then drop the frame else forward the frame on interface indicated } else flood forward on all but the interface on which the frame arrived 5: DataLink Layer

369 address interface switch 1 A B E G 1 2 3 2 3 hub hub A hub C 1 I D F BSwitch example Suppose C sends frame to D address interface switch 1 A B E G 1 2 3 2 3 hub hub A hub C 1 I D F B G C H E Switch receives frame from from C notes in bridge table that C is on interface 1 because D is not in table, switch forwards frame into interfaces 2 and 3 frame received by D 5: DataLink Layer

370 address interface switch 1 A B E G C 1 2 3 2 3 hub hub hub A I D 2 D FSwitch example Suppose D replies back with frame to C. address interface switch 1 A B E G C 1 2 3 2 3 hub hub hub A I D 2 D F B G C H E Switch receives frame from from D notes in bridge table that D is on interface 2 because C is in table, switch forwards frame only to interface 1 frame received by C 5: DataLink Layer

371 Switch: traffic isolationswitch installation breaks subnet into LAN segments switch filters packets: same-LAN-segment frames not usually forwarded onto other LAN segments segments become separate collision domains hub switch collision domain collision domain 5: DataLink Layer collision domain

372 Switches and Spanning Treesfor increased reliability, desirable to have redundant, alternate paths from source to destination with multiple simultaneous paths, cycles result - bridges may multiply and forward frame forever solution: organize switches in a spanning tree by disabling subset of interfaces Disabled switch switch 5: DataLink Layer

373 Switches vs. Routers both store-and-forward devicesrouters: network layer devices (examine network layer headers) switches/bridges are link Layer devices routers maintain routing tables, implement routing algorithms swtiches maintain filtering tables, implement filtering, learning and spanning tree algorithms 5: DataLink Layer

374 Routers vs. Switches Switches + and -+ Switch operation is simpler requiring less processing bandwidth - Topologies are restricted with switches: avoid cycles with spanning trees - Switches do not offer protection from broadcast storms (endless broadcasting by a host will be forwarded by a switch) 5: DataLink Layer

375 Routers vs. Switches Routers + and -+ arbitrary topologies can be supported, cycling is limited by TTL counters (and good routing protocols) - require IP address configuration (not plug and play) - require higher processing bandwidth switches do well in small (few hundred hosts) while routers used in large networks (thousands of hosts) 5: DataLink Layer

376 Summary comparison 5: DataLink Layer

377 Link Layer 5.1 Introduction and services5.2 Error detection and correction 5.3Multiple access protocols 5.4 Link-Layer Addressing 5.5 Ethernet and other data link layers 5.6 Hubs and switches 5.7 PPP 5.8 Link Virtualization: ATM 5: DataLink Layer

378 Point to Point Data Link ControlPoint-to-point links One sender, one receiver, one link Easier than shared broadcast links No media access control No need for explicit MAC addressing (ie ARP) Goal of Point-to-Point protocols Layer generic “higher-level” data-link layer functions on top of a variety of point-to-point links Dial-up phone line, DSL, ISDN etc. Each different link does its own digital-analog conversion (ie provides bits) Implement pseudo-link layer on top that implements common functions Framing, Demux to upper layer, etc. Examples PPP (point-to-point protocol) HDLC: High level data link control (Data link used to be considered “high layer” in protocol stack!) 5: DataLink Layer

379 PPP Design Requirements [RFC 1557]packet framing: encapsulation of network-layer datagram in data link frame carry network layer data of any network layer protocol (not just IP) at same time demultiplex upwards bit transparency: must carry any bit pattern in the data field error detection (no correction) connection liveness: detect, signal link failure to network layer network layer address negotiation: endpoint can learn/configure each other’s network address 5: DataLink Layer

380 PPP non-requirements no error correction/recovery no flow controlout of order delivery OK no need to support multipoint links (e.g., polling) Error recovery, flow control, data re-ordering all relegated to higher layers! 5: DataLink Layer

381 PPP Data Frame Flag: delimiter (framing)Address: does nothing (only one option) Control: does nothing; in the future possible multiple control fields Protocol: upper layer protocol to which frame delivered (eg, PPP-LCP, IP, IPCP, etc) 5: DataLink Layer

382 PPP Data Frame info: upper layer data being carriedcheck: cyclic redundancy check for error detection 5: DataLink Layer

383 Byte Stuffing “data transparency” requirement: data field must be allowed to include flag pattern < > Q: is received < > data or flag? Sender: adds (“stuffs”) extra < > byte before each < > data byte adds (“stuffs”) extra < > byte before each < > data byte Receiver: byte followed by byte: discard first byte, continue data reception single : flag byte 5: DataLink Layer

384 stuffed byte in transmitted dataByte Stuffing flag byte pattern in data to send flag byte pattern plus stuffed byte in transmitted data 5: DataLink Layer

385 PPP Data Control ProtocolBefore exchanging network-layer data, data link peers must configure PPP link (max. frame length, authentication) learn/configure network layer information for IP: carry IP Control Protocol (IPCP) msgs (protocol field: 8021) to configure/learn IP address 5: DataLink Layer

386 Link Layer 5.1 Introduction and services5.2 Error detection and correction 5.3Multiple access protocols 5.4 Link-Layer Addressing 5.5 Ethernet and other data link layers 5.6 Hubs and switches 5.7 PPP 5.8 Link Virtualization: ATM and MPLS 5: DataLink Layer

387 Virtualization of networksVirtualization of resources: a powerful abstraction in systems engineering: computing examples: virtual memory, virtual devices Virtual machines: e.g., java IBM VM os from 1960’s/70’s layering of abstractions: don’t sweat the details of the lower layer, only deal with lower layers abstractly 5: DataLink Layer

388 The Internet: virtualizing networks1974: multiple unconnected nets ARPAnet data-over-cable networks packet satellite network (Aloha) packet radio network … differing in: addressing conventions packet formats error recovery routing ARPAnet satellite net "A Protocol for Packet Network Intercommunication", V. Cerf, R. Kahn, IEEE Transactions on Communications, May, 1974, pp 5: DataLink Layer

389 The Internet: virtualizing networksInternetwork layer (IP): addressing: internetwork appears as a single, uniform entity, despite underlying local network heterogeneity network of networks Gateway: “embed internetwork packets in local packet format or extract them” route (at internetwork level) to next gateway gateway ARPAnet satellite net 5: DataLink Layer

390 Cerf & Kahn’s Internetwork ArchitectureWhat is virtualized? two layers of addressing: internetwork and local network new layer (IP) makes everything homogeneous at internetwork layer underlying local network technology cable satellite 56K telephone modem today: ATM, MPLS … “invisible” at internetwork layer. Looks like a link layer technology to IP! 5: DataLink Layer

391 Virtual links and tunnelingMany options of encapsulating or tunneling packets through a “virtual link” (VPN) Generic Routing Encapsulation (GRE) PPTP (Point-to-point Tunneling Protocol) L2F (Layer 2 Forwarding) L2TP (Layer 2 Tunneling Protocol) Can also be done at network layer via IPsec Encrypt data at a layer below network layer Works for IP packets 5: DataLink Layer

392 VPN server terminates tunnelVirtual links example Treat IP-to-IP session as a virtual LAN link IP_local = IP addr. of client at home assigned by ISP IP_work = IP addr. of client for use in accessing work LAN IP_file_serv = IP addr. of protected file server at work ACL to only allow access from work LAN IP_VPN_serv = IP addr. of VPN server at work Authenticates remote client via username/password Assigns remote client an IP address on LAN (IP_work) Responds to ARPs for IP_remote on behalf of client Decapsulates and encapsulates packets to/from client IP Src = IP_work IP Src = IP_local IP Src = IP_file_serv IP Dst = IP_VPN_serv VPN server terminates tunnel IP Src = IP_work IP Src = IP_file_serv 5: DataLink Layer

393 ATM and MPLS ATM, MPLS separate networks in their own rightdifferent service models, addressing, routing from Internet viewed by Internet as logical link connecting IP routers just like dialup link is really part of separate network (telephone network) 5: DataLink Layer

394 Multiprotocol label switching (MPLS)initial goal: speed up IP forwarding by using fixed length label (instead of IP address) to do forwarding borrowing ideas from Virtual Circuit (VC) approach but IP datagram still keeps IP address! Data-link header MPLS header IP header remainder of payload label Exp S TTL 20 3 1 5 5: DataLink Layer

395 MPLS capable routers a.k.a. label-switched routerforwards packets to outgoing interface based only on label value (don’t inspect IP address) MPLS forwarding table distinct from IP forwarding tables signaling protocol needed to set up forwarding RSVP-TE forwarding possible along paths that IP alone would not allow (e.g., source-specific routing) !! use MPLS for traffic engineering must co-exist with IP-only routers 5: DataLink Layer

396 MPLS forwarding tablesin out out label label dest interface A in out out label label dest interface A D D A R6 D 1 1 R4 R3 R5 A R2 in out out label label dest interface A R1 in out out label label dest interface A 5: DataLink Layer

397 Chapter 5: Summary principles behind data link layer services:error detection, correction sharing a broadcast channel: multiple access link layer addressing instantiation and implementation of various link layer technologies Ethernet switched LANS PPP virtualized networks as a link layer: ATM, MPLS 5: DataLink Layer

398 Physical Layer Functions Digital to Analog conversionPhysical media characteristics 5: DataLink Layer

399 Digital to analog conversionBits sent as analog signals Photonic pulses of a given wavelength over optical fiber Electronic signals of a given voltage 5: DataLink Layer

400 Digital to analog conversionWill cover electronic transmission (optical transmission left for you to research) Biggest issue When to sample voltage? Detecting sequences involves clocking with the same clock How to synchronize sender and receiver clocks? Need easily detectible event at both ends Signal transitions help resync sender and receiver Need frequent transitions to prevent clock skew 5: DataLink Layer

401 NRZ-L Non-Return to Zero Level (NRZ-L) 1=high signal, 0=lower signalLong sequence of same bit causes difficulty DC bias hard to detect – low and high detected by difference from average voltage Clock recovery difficult Used by Synchronous Optical Network (SONET) SONET XOR’s bit sequence to ensure frequent transitions Used in early magnetic tape storage Draw = LHLH 5: DataLink Layer

402 NRZ-L 5: DataLink Layer

403 NRZ-M Non-Return to Zero Mark Less power to transmit versus NRZ1=signal transition at start of bit, 0=no change No problem with string of 1’s NRZ-like problem with string of 0’s Used in SDLC (Synchronous Data Link Control) Used in modern magnetic tape storage Draw = LHLH 5: DataLink Layer

404 Manchester (Bi-Phase-Level) coding0=low to high transition, 1=high to low transition Transition for every bit simplifies clock recovery Not very efficient Doubles the number of transitions Circuitry must run twice as fast Used by Ethernet = H LH HL LH HL 5: DataLink Layer

405 Manchester coding Encoding for 110100 Bit stream 1 1 11 Manchester encoding 5: DataLink Layer

406 Physical Layer Plethora of physical media Fiber, copper, airSpecifies the characteristics of transmission media Too many to cover in detail, not the focus of the course Many data-link layer protocols (i.e. Ethernet, Token-Ring, FDDI. ATM run across multiple physical layers) Physical characteristics dictate suitability of data-link layer protocol and bandwidth limits 5: DataLink Layer

407 Common Cabling Copper Fiber Twisted Pair Coaxial Cable Single-modeUnshielded (UTP) CAT-1, CAT-2, CAT-3, CAT-4, CAT-5, CAT-5e Shielded (STP) Coaxial Cable Fiber Single-mode Multi-mode 5: DataLink Layer

408 Twisted Pair Most common LAN interconnectionMultiple pairs of twisted wires Twisting to eliminate interference More twisting = Higher data rates, higher cost 5: DataLink Layer

409 Twisted pair Standards specify twisting, resistance, and maximum cable length for use with particular data-link layer 5 categories Category 1 Voice only (telephone wire) Category 2 Data to 4Mbs (LocalTalk) Category 3 Data to 10Mbs (Ethernet) Category 4 Data to 20Mbs (16Mbs Token Ring) Category 5 (100 MHz) Data to 100Mbs (Fast Ethernet) Category 5e (350 MHz) Data to 1000Mbs (Gigabit Ethernet) 5: DataLink Layer

410 Twisted Pair Common connectors for Twisted Pair RJ11 (3 pairs)Phone connections RJ45 (4 pairs) Allows both data and phone connections (1,2) and (3,6) for data (4,5) for voice (7,8) unused Crossover cables for NIC-NIC, Hub-Hub connection (Data pairs swapped) 5: DataLink Layer

411 UTP Unshielded Twisted PairLimited amount of protection from interference Commonly used for voice and ethernet Voice: multipair 100-ohm UTP 5: DataLink Layer

412 STP Shielded Twisted Pair Not as common at UTPUTP susceptible to radio and electrical interference Extra shielding material added Cables heavier, bulkier, and more costly Often used in token ring topologies 150 ohm STP two pair (IEEE Token Ring) 5: DataLink Layer

413 Coaxial cable Two concentric copper conductorsBidirectional Separated by plastic insulation layer Support longer connectivity distances over UTP Used in CATV networks HFC networks (Hybrid Fiber/Coax) Fiber from cable headend to location near home Coax to home FDM to support multiple data channels 5: DataLink Layer

414 Fiber Transmit light pulses vs. electronic signals CablingImmune to electromagnetic noise/interference high-speed point-to-point transmission (e.g., 10’s-100’s Gps) Low error rate Cabling Center core made of glass or plastic fiber Plastic coating to cushion core Kevlar fiber for strength Teflon or PVC outer insulating jacket 5: DataLink Layer

415 Fiber Single-mode fiber Multi-mode fiber Photodiodes at receiversSmaller diameter (12.5 microns) One mode only Preserves signal better over longer distances Typically used for SONET or SDH Lasers used to signal Multi-mode fiber Larger diameter (62.5 microns) Multiple modes WDM and DWDM = (dense) wavelength division multiplexing Photodiodes at receivers 5: DataLink Layer

416 Physical-link lingo Specifies capacities over physical mediaElectronic T1/DS1=1.54 Mbps T3/DS3=45Mbps Optical (OC=optical carrier) OC1=52 Mbps OC3/STM1=156 Mbps OC12=622 Mbps OC48=2488 Mbps OC192=10 Gbps OC768=40 Gbps 5: DataLink Layer

417 Wireless Entire spectrum of transmission frequency rangesRadio Infrared Lasers Cellular telephone Microwave Satellite Acoustic (see ESE sensors) Ultra-wide band propagation environment effects: reflection obstruction by objects interference 5: DataLink Layer

418 5: DataLink Layer

419 What runs on them? Protocol Summary 5: DataLink Layer Protocol CableSpeed Topology Ethernet Twisted Pair, Coaxial, Fiber 10 Mbps Linear Bus, Star, Tree Fast Ethernet Twisted Pair, Fiber 100 Mbps Star LocalTalk Twisted Pair .23 Mbps Linear Bus or Star Token Ring 4 Mbps - 16 Mbps Star-Wired Ring FDDI Fiber Dual ring ATM Mbps 5: DataLink Layer

420 Extra slides 5: DataLink Layer

421 ARQ Automatic Repeat Request (ARQ)Receiver sends acknowledgement (ACK) when it receives packet Sender waits for ACK and timeouts if it does not arrive within some time period 5: DataLink Layer

422 Stop and Wait Simplest ARQ protocolSend a packet, stop and wait until acknowledgement arrives Sender Receiver Packet Time Timeout ACK 5: DataLink Layer

423 Recovering from Error Packet Packet Packet Timeout Timeout Timeout ACKApplication may get duplicates in the case of early timeouts ACK lost Packet lost Early timeout 5: DataLink Layer

424 Stop and Wait Problems How to recognize a duplicate? PerformanceCan only send one packet per round trip 5: DataLink Layer

425 How to Recognize Resends?Use sequence numbers both packets and acks Sequence # in packet is finite -- how big should it be? For stop and wait? One bit – won’t send seq #1 until received ACK for seq #0 Pkt 0 ACK 0 Pkt 0 ACK 0 Pkt 1 ACK 1 5: DataLink Layer

426 How to Keep the Pipe Full?Send multiple packets without waiting for first to be acked Number of pkts in flight = window How large a window is needed Round trip delay * bandwidth = capacity of pipe Reliable, unordered delivery Several parallel stop & waits Send new packet after each ack Sender keeps list of unack’ed packets; resends after timeout Receiver same as stop&wait 5: DataLink Layer

427 Sliding Window Reliable, ordered deliveryReceiver has to hold onto a packet until all prior packets have arrived Sender must prevent buffer overflow at receiver Circular buffer at sender and receiver Packets in transit <= buffer size Advance when sender and receiver agree packets at beginning have been received 5: DataLink Layer

428 Sender/Receiver StateMax ACK received Next seqnum Next expected Max acceptable … … … … Sender window Receiver window Sent & Acked Sent Not Acked Received & Acked Acceptable Packet OK to Send Not Usable Not Usable 5: DataLink Layer

429 Window Sliding – Common CaseOn reception of new ACK (i.e. ACK for something that was not acked earlier Increase sequence of max ACK received Send next packet On reception of new in-order data packet (next expected) Hand packet to application Send cumulative ACK – acknowledges reception of all packets up to sequence number Increase sequence of max acceptable packet 5: DataLink Layer

430 Loss Recovery On reception of out-of-order packetSend nothing (wait for source to timeout) Cumulative ACK (helps source identify loss) Timeout (Go Back N recovery) Set timer upon transmission of packet Retransmit max ACK received sequence + 1 Restart from max ACK received sequence + 1 Performance during loss recovery No longer have an entire window in transit Can have much more clever loss recovery Covered in TCP lectures 5: DataLink Layer

431 Sequence Numbers How large do sequence numbers need to be? E.g.Must be able to detect wrap-around Depends on sender/receiver window size E.g. Max seq = 7, send win=recv win=7 If pkts 0..6 are sent succesfully and all acks lost Receiver expects 7,0..5, sender retransmits old 0..6 Max sequence must be >= send window + recv window Xxx picture 5: DataLink Layer

432 Checksumming: Cyclic Redundancy Checkview data bits, D, as a binary number choose r+1 bit pattern (generator), G goal: choose r CRC bits, R, such that exactly divisible by G (modulo 2) receiver knows G, divides by G. If non-zero remainder: error detected! can detect all burst errors less than r+1 bits widely used in practice (ATM, HDCL) 5: DataLink Layer

433 RZ Return to Zero (RZ) 1=pulse to high, dropping back to low0=no transition 5: DataLink Layer

434 NRZ-S Non-Return to Zero Space1=no change, 0=signal transition at start of bit No problem with string of 0’s NRZ-like problem with string of 1’s Draw = LHLH 5: DataLink Layer

435 Manchester encoding Used in 10BaseT Each bit has a transitionAllows clocks in sending and receiving nodes to synchronize to each other no need for a centralized, global clock among nodes! Hey, this is physical-layer stuff! More later 5: DataLink Layer

436 Other coding schemes Bi-Phase-Mark, Bi-Phase-SpaceLevel change at every bit period boundary Mid-period transition determines bit Bi-Phase-M: 0=no change, 1=signal transition Bi-Phase-S: 0=signal transition, 1=no change 5: DataLink Layer

437 Other coding schemes Differential Bi-Phase-Space, Differential Bi-Phase-Mark Level change at every mid-bit period boundary Bit period boundary transition determines bit Diff-Bi-Phase-M: 0=signal transition, 1=no change Diff-Bi-Phase-S: 0=no change, 1=signal transition 5: DataLink Layer

438 802.3 Ethernet Standards: Link & Physical Layersmany different Ethernet standards common MAC protocol and frame format different speeds: 2 Mbps, 10 Mbps, 100 Mbps, 1Gbps, 10G bps different physical layer media: fiber, cable MAC protocol and frame format application transport network link physical copper (twisted pair) physical layer 100BASE-TX fiber physical layer 100BASE-T2 100BASE-FX 100BASE-T4 100BASE-SX 100BASE-BX 5: DataLink Layer

439 10BaseT and 100BaseT 10/100 Mbps rate; latter called “fast ethernet”T stands for Twisted Pair Originally, half-duplex mode Bus topology popular through mid 90s (10Base2, co-ax) Eventually, nodes connect to a hub: “star topology”; 100 m max distance between nodes and hub Nodes at both ends of link can not transmit at same time Nodes can not transmit and receive at same time Today, mostly full-duplex Nodes connect to switches Simultaneous xmit and receive twisted pair hub 5: DataLink Layer

440 Gbit Ethernet uses standard Ethernet frame formatallows for point-to-point links and shared broadcast channels in shared mode, CSMA/CD is used; short distances between nodes required for efficiency Full-Duplex at 1 Gbps for point-to-point links Nodes can transmit and receive at 1Gbps simultaneously 10 Gbps now ! 5: DataLink Layer

441 Backbone Bridge 5: DataLink Layer

442 Interconnection Without BackboneNot recommended for two reasons: - single point of failure at Computer Science hub - all traffic between EE and SE must path over CS segment 5: DataLink Layer

443 CSMA/CD efficiency Tprop = max prop delay between 2 nodes in LANttrans = time to transmit max-size frame efficiency goes to 1 as tprop goes to 0 as ttrans goes to infinity better performance than ALOHA: and simple, cheap, decentralized! 5: DataLink Layer

444 More on Switches cut-through switching: frame forwarded from input to output port without first collecting entire frame slight reduction in latency combinations of shared/dedicated, 10/100/1000 Mbps interfaces 5: DataLink Layer

445 Institutional networkmail server to external network web server router switch IP subnet hub hub hub 5: DataLink Layer

446 Ethernet: uses CSMA/CDif packet then { A: sense channel if idle transmit and monitor the channel; if detect another transmission abort and send jam signal; update # collisions; delay as required by exponential backoff algorithm; goto A } else {done with the frame; set collisions to zero} else {wait until ongoing transmission is over and goto A} 5: DataLink Layer

447 10Base2 Ethernet Sifting through the jargon (10Base2)10: 10Mbps; 2: under 200 meters max cable length thin coaxial cable in a bus topology repeaters used to connect up to multiple segments repeater repeats bits it hears on one interface to its other interfaces: physical layer device only! 5: DataLink Layer

448 ATM ATM Covered as a data-link layer…Replace existing Internet protocols with a more “robust” architecture Network architecture to support Multiple service classes and per-flow guarantees Virtual circuits to support real-time applications Explicit rate signaling and resource allocation Covered as a data-link layer… 5: DataLink Layer

449 Internet vs. ATM ATM Internet“elastic” datagram service, no strict timing req. Computer communication only “smart” end systems (computers) can adapt, perform control, error recovery simple inside network, complexity at “edge” many link types different characteristics uniform service difficult ATM evolved from telephony, strict timing and reliability requirements Computer and human communication need for guaranteed service “dumb” end systems telephones complexity inside network 5: DataLink Layer

450 Asynchronous Transfer Mode (ATM)1980s/1990’s standard for high-speed (155Mbps to 622 Mbps and higher) Broadband Integrated Service Digital Network architecture Take strengths of IP, learn from its shortcomings Packet switching good Packet switching without explicit network-level connections and reservations bad Packet switching using large headers for small packets bad (voice) Design new network to address emerging applications while allowing for efficient support for non-real-time data applications Goal: integrated, end-end transport of carry voice, video, data meeting timing/QoS requirements of voice, video (versus Internet best-effort model) “next generation” telephony: technical roots in telephone world packet-switching (fixed length packets, called “cells”) using virtual circuits Covered now since it is used mostly as a data-link layer 5: DataLink Layer

451 ATM architecture adaptation layer: only at edge of ATM networkdata segmentation/reassembly roughly analagous to Internet transport layer ATM layer: “network” layer cell switching, routing physical layer 5: DataLink Layer

452 ATM: network or link layer?Vision: end-to-end transport: “ATM from desktop to desktop” ATM is a network technology Reality: used to connect IP backbone routers “IP over ATM” ATM as switched link layer, connecting IP routers IP network ATM network 5: DataLink Layer

453 ATM Adaptation Layer (AAL)ATM Adaptation Layer (AAL): “adapts” upper layers (IP or native ATM applications) to ATM layer below AAL present only in end systems, not in switches AAL layer segment (header/trailer fields, data) fragmented across multiple ATM cells analogy: TCP segment in many IP packets 5: DataLink Layer

454 ATM Adaptation Layer (AAL) [more]Different versions of AAL layers, depending on ATM service class: AAL1: for CBR (Constant Bit Rate) services, e.g. circuit emulation AAL2: for VBR (Variable Bit Rate) services, e.g., MPEG video AAL5: for data (eg, IP datagrams) User data AAL PDU ATM cell 5: DataLink Layer

455 ATM Layer Service: transport cells across ATM networkanalogous to IP network layer very different services than IP network layer Guarantees ? Network Architecture Internet ATM Service Model best effort CBR VBR ABR UBR Congestion feedback no (inferred via loss) no congestion yes Bandwidth none constant rate guaranteed minimum Loss no yes Order no yes Timing no yes 5: DataLink Layer

456 ATM Layer: Virtual CircuitsVC transport: cells carried on VC from source to dest call setup, teardown for each call before data can flow each packet carries VC identifier (not destination ID) every switch on source-dest path maintain “state” for each passing connection link,switch resources (bandwidth, buffers) may be allocated to VC: to get circuit-like perf. Permanent VCs (PVCs) long lasting connections typically: “permanent” route between to IP routers Switched VCs (SVC): dynamically set up on per-call basis 5: DataLink Layer

457 ATM VCs Advantages of ATM VC approach:QoS performance guarantee for connection mapped to VC (bandwidth, delay, delay jitter) Drawbacks of ATM VC approach: Inefficient support of datagram traffic one PVC between each source/dest pair) does not scale (N*2 connections needed) SVC introduces call setup latency, processing overhead for short lived connections 5: DataLink Layer

458 ATM Layer: ATM cell 5-byte ATM cell header 48-byte payloadWhy?: small payload -> short cell-creation delay for digitized voice halfway between 32 and 64 (compromise!) Cell header Cell format 5: DataLink Layer

459 ATM cell header VCI: virtual channel IDwill change from link to link thru net PT: Payload type (e.g. RM cell versus data cell) CLP: Cell Loss Priority bit CLP = 1 implies low priority cell, can be discarded if congestion HEC: Header Error Checksum cyclic redundancy check 5: DataLink Layer

460 ATM Physical Layer (more)Two pieces (sublayers) of physical layer: Transmission Convergence Sublayer (TCS): adapts ATM layer above to PMD sublayer below Physical Medium Dependent: depends on physical medium being used TCS Functions: Header checksum generation: 8 bits CRC Cell delineation With “unstructured” PMD sublayer, transmission of idle cells when no data cells to send 5: DataLink Layer

461 ATM Physical Layer Physical Medium Dependent (PMD) sublayerSONET/SDH: transmission frame structure (like a container carrying bits); bit synchronization; bandwidth partitions (TDM); several speeds: OC3 = Mbps; OC12 = Mbps; OC48 = 2.45 Gbps, OC192 = 9.6 Gbps TI/T3: transmission frame structure (old telephone hierarchy): 1.5 Mbps/ 45 Mbps unstructured: just cells (busy/idle) 5: DataLink Layer

462 IP-Over-ATM ATM network Ethernet Ethernet LANs LANs IP over ATMreplace “network” (e.g., LAN segment) with ATM network ATM addresses, IP addresses Classic IP only 3 “networks” (e.g., LAN segments) MAC (802.3) and IP addresses ATM network Ethernet LANs Ethernet LANs 5: DataLink Layer

463 IP-Over-ATM AAL ATM phy Eth IP app transport 5: DataLink Layer

464 Datagram Journey in IP-over-ATM Networkat Source Host: IP layer maps between IP, ATM dest address (using ARP) passes datagram to AAL5 AAL5 encapsulates data, segments cells, passes to ATM layer ATM network: moves cell along VC to destination at Destination Host: AAL5 reassembles cells into original datagram if CRC OK, datagram is passed to IP 5: DataLink Layer

465 IP-Over-ATM ATM network Ethernet LANs Issues:IP datagrams into ATM AAL5 PDUs from IP addresses to ATM addresses just like IP addresses to MAC addresses! ATM network Ethernet LANs 5: DataLink Layer

466 ATM and “IP switching” ATM advantages ATM disadvantages Goal SolutionLookup of VCID = O(1), Lookup of IP routes O(log n) One-time route lookup and circuit establishment, all subsequent traffic switched ATM disadvantages Complex signaling and routing for establishing communication Difficulty in mapping IP traffic dynamically onto ATM circuits Goal Maintain IP infrastructure Accelerate it with labels to support O(1) lookups a la ATM Solution Ipsilon and “IP switching” 5: DataLink Layer

467 IP over ATM versus IP switchingATM network control ATM label switching IP network control IP routing IP network control IP routing IP network control ATM label switching IP network control IP routing IP network control IP routing 5: DataLink Layer

468 ATM and “IP switching” In a nutshell Operation Start with ATM switchRip out ATM signaling and routing Add IP routing software Add Flow classifier to map unknown flows to underlying ATM virtual circuit ID Attach VCID and allow downstream nodes to do the same Operation Upon arrival of first packet in flow Record unknown incoming VCID Lookup IP flow and map it to an outgoing virtual circuit ID (label) using IP routing software Create incomingVCID to outgoingVCID table entry for subsequent packets Subsequent packets Switched in hardware using VCID after flow classified at edge IP packet forwarding done as label index lookup O(1) versus IP route lookup O(log n) 5: DataLink Layer

469 ATM and “IP switching” Later generalized as MPLS (multi-protocol label switching) “Layer 2 ½” Not tied to ATM Extensible to IPv6 Half-way in between data-link addresses and IP addresses Labeling done within a cloud versus link-local (data-link addresses) and global (IP addresses) Used as a tool for traffic engineering 5: DataLink Layer

470 X.25 and Frame Relay Like ATM: wide area network technologiesvirtual circuit oriented origins in telephony world Not really a link layer but.... Viewed as link layers by IP protocol Used mostly to carry IP datagrams between IP routers Going the way of the dinosaurs.... 5: DataLink Layer

471 X.25 X.25 builds VC between source and destination for each user connection Per-hop control along path error control (with retransmissions) on each hop using LAP-B variant of the HDLC protocol developed when bit error rates over long-haul copper links were orders of magnitude higher per-hop flow control using credits congestion arising at intermediate node propagates to previous node on path back to source via back pressure 5: DataLink Layer

472 IP versus X.25 X.25: reliable in-sequence end-end delivery from end-to-end “intelligence in the network” built for dumb terminals accessing mainframes IP: unreliable, out-of-sequence end-end delivery “intelligence in the endpoints” 2000 gigabit routers: limited processing possible CPU capacity at end-hosts IP wins 5: DataLink Layer

473 Frame Relay Designed in late ‘80s, widely deployed in the ‘90sSecond-generation X.25 Frame relay service: no error control no flow control End-to-end congestion control Some QoS mechanisms 5: DataLink Layer

474 Frame Relay (more) Designed to interconnect corporate customer LANstypically permanent VC’s: “pipe” carrying aggregate traffic between two routers switched VC’s: as in ATM corporate customer leases FR service from public Frame Relay network (eg, Sprint, ATT) 5: DataLink Layer

475 Frame Relay (more) 10 bit VC ID field 3 congestion control bitsaddress flags data CRC Flag bits, , delimit frame address: 10 bit VC ID field 3 congestion control bits FECN: forward explicit congestion notification (frame experienced congestion on path) BECN: congestion on reverse path DE: discard eligibility Precursor to IP DiffServ and ECN 5: DataLink Layer

476 Frame Relay -VC Rate ControlCommitted Information Rate (CIR) defined, “guaranteed” for each VC negotiated at VC set up time customer pays based on CIR DE bit: Discard Eligibility bit Edge FR switch measures traffic rate for each VC; marks DE bit DE = 0: high priority, rate compliant frame; deliver at “all costs” DE = 1: low priority, eligible for discard when congestion Precursor to IP DiffServ Can be used to support higher layer QoS mechanisms 5: DataLink Layer

477 Coaxial cable Thick (10Base5) Thin (10Base2) cables Video cableLarge diameter 50-ohm cable N connectors Thin (10Base2) cables Small diameter 50-ohm cable BNC, RJ-58 connector Video cable 75-ohm cable BNC, RJ-59 connector Not compatible with RJ-58 5: DataLink Layer

478 Fiber connectors ESCON Duplex SC ST MT-RJ (multimode) Duplex LC5: DataLink Layer