2. Connection Services Abdulaziz S. Almulhem, Ph.D almulhem@ccse.kfupm.edu.sa Department of Computer Engineering King Fahd University of Petroleum and Minerals Dhahran, Saudi Arabia

3. Connection services l What is connection services? l POTS l X.25 l ATM l ADSL

4. Introduction lUlUsers lClCommunication networks lSlServices

5. POTS l Plain Old Telephone Set l Basic service l No flow control l Low speed networking

6. 1970s l IBM/SNA (1974) l Digital/DECnet (1975) l Sperry-Univac/Data communication architecture (1976) l Siemens/TRANSDATA (1978) l Honeywell/Distributed system architecture (1979)

7. X.25 (1/2) l CCITT (ITU-T) 1970-74 l Interfacing host to public data network l Link access protocol B (LAP B) l Go Back N l Window size 8 or 128 (satellite) l Bit stuffing

8. X.25 (2/2) Packet Switch Network

9. ATM (1/2) l Asynchronous Transfer Mode l Cell based switching technology l Integrate different data types l Traffic management (contracting, policing,…etc.) l high speed (OC192)

10. ATM (2/2) VC VP

11. DSL (1/2) l Digital subscriber line l started with 2B+D; now 52 Mbps! l Different flavors are available. l Uses TCM (Time Compress Multiplexing) for data transmission l Intense bit encoding per symbol l RS coding

12. DSL (2/2) 101001000 Frequency (kHz) POTSUpstreamDownstream

13. Connection services Call Setup (SS7 or other) Time-Division Multiplexed Circuits (56/64K or T1/E1) X.25/Frame Relay Networks Central office (CO) CO

14. Summary l High speed communication. l Low operational and management costs. l support new needs. l Simplicity is the keyword.

15. References l W. Stallings, “High-Speed Network”, Prentice-Hall, 1998. l W. Chen, “DSL”, MacmillanTechnical Publishing, 1998. l J. Walrand, “Communication Networks”, Asken Associates, 1991.

16. WWW Sites l ATM Forum: www.atmforum.com l Frame Relay Forum: www.frforum.com l More FR stuff: www.mot.co/MIMS/ISG/tech/frame-relay/resources.html l DSL Forum: www.adsl.com l IETF (Internet): www.ietf.org