1 Kommunikatsiooniteenuste arendus IRT0080Loeng 2 Avo Ots telekommunikatsiooni õppetool, TTÜ raadio- ja sidetehnika inst.

2 Every machine transparently connected to every otherThe Internet Every machine transparently connected to every other

3 Piirkonnad ja piirpinnadT T T GW SCN GW GW GK MCU Packet Network T T

4 The Problem only nodes on the same physical/link layer network could communicate

5 Solution Gateways

6 Classification of Multiple Access ProtocolsContention-based Conflict-free Random access Collision resolution ALOHA, CSMA, BTMA, ISMA, etc TREE, WINDOW, etc FDMA, TDMA, CDMA, Token Bus, DQDB, etc BTMA: Busy Tone Multiple Access ISMA: Internet Streaming Media Alliance DQDB: Distributed Queue Dual Bus

7 Channel Sharing TechniquesStatic Channelization Channel Sharing Techniques Scheduling Dynamic Medium Access Control Random Access

8 Throughput 0.368 S Slotted Aloha 0.184 Aloha G

9 Vastastikused häired

10 Kvaliteet IP-võrgu kaudu(LAN) Router Peakorter Harukontor (WAN) QoS

11 Network structure (TUT)public access networks (PAN) isolated from other networks in the edge routers access from PAN to Internet controlled by access controllers department ”intranets” may be protected with access control lists / filters in the edge routers VLANs are used to separate access controllers to own access controller segment public access network is considered a hostile network like the Internet access controller Internet Main house ”intra” networks TUT core network Main house public access network public access networks (PAN) isolated from other networks in the edge routers access from PAN to Internet controlled by access controllers department ”intranets” may be protected with access control lists / filters in the edge routers VLANs are used to separate access controllers to own access controller segment public access network is considered a hostile network like the Internet Tietotalo public access network Tietotalo ”intra” networks

12 Network elements (TUT)TUT core network Internet department x ”intranet” department y ”intranet” VPN terminator Access Controllers public access zone e.g. teamwork room IPSEC/VPN secured access to department ”intranet” access zone consists of several access points preferably in the same IP network IPSEC/VPN secured access also available from the public access zone Public Access also available from the combined employee/public access zone The same radio network is used to deliver services to both the employees and the guests/students. The goal is to have no overlapping networks, instead one combined radio network providing coverage to all. combined department employee/public access zone Nonencrypted filtered access to Internet public access zone e.g lecture hall

13 Sidesüsteemi mõjutavadFraud Hacker Internet VPN Fraud Interception Fraud Viruses