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Emerged Technologies ISDN

Emerged Technologies ISDN. Nirmala Shenoy Information Technology Dept Rochester Institute of Technology. ISDN. Purpose Digital interface between user and network An all digital network to support the transport for digitized information

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Emerged Technologies ISDN

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  1. Emerged TechnologiesISDN Nirmala Shenoy Information Technology Dept Rochester Institute of Technology

  2. ISDN • Purpose • Digital interface between user and network • An all digital network to support the transport for digitized information • For the user the type of transport network is transparent, voice, video, data • ISDN nodes provides this transparency • Based on technologies used in T1/E1

  3. ISDN • Topology • Similar to X.25 • UNI protocol • Comprises of • Functional groupings • Set of capabilities, • Multiple pieces of equipment or software

  4. ISDN • Topology • Comprises of • Reference Points • Interfaces between the functional groupings • Physical interface between two pieces of equipment

  5. ISDN • Topology

  6. ISDN • Topology • Functional Groupings • TE1 • Terminal equipment type 1 – ISDN compatible equipment • Uses twisted pair – 4 wire digital link

  7. ISDN • Topology • Functional Groupings • NT2 -Network Termination type 2 • An intelligent equipment, layer 2 & 3 functions • Concentration, multiplexing of channels to a defined rate • Support multiple terminals

  8. ISDN • Topology • Functional Groupings • NT1 -Network Termination type 1 • Connects 4 wire subscriber to 2 wire local loop • Physical layer – signaling, synchronization and timing • TEs can connect direct to NT1 – can address up to 8 TEs • NT1 + NT2 = NT12 - combined functions

  9. ISDN • Topology • Functional Groupings • TE2 – non-ISDN compatible TE type 2 • Requires an adapter to connect to ISDN • TA – Terminal Adapter • provides adaptive function for non-ISDN terminals

  10. ISDN • Topology • Reference points • S – logical interface between TE and network • R – between non-ISDN TE and adapter • U – 2 wire side of the NT equipment • TE – user related , NT – Network related

  11. ISDN • Topology • TDM based • 2B + D channels – Basic Rate Interface- BRI • B – user data – 64 Kbps • D – signaling – 16kbs – out-of band • 8 TE1s can share a 2B+D channel

  12. ISDN • Topology • PRI – Primary Rate interface • 23B + D channels – NA & Japan • 1.544 Mbps • 31B + D channels – Europe • 2.048 Mbps

  13. ISDN • Layers

  14. ISDN • Layers • 3 layers, Network, data link and physical • Physical – • Basic Rate Interface & Primary Rate Interface • Data Link layer • LAPD – Link Access Procedures for D channel

  15. ISDN • Layers • Network Layer – Q.931 • Establishing and releasing connection

  16. ISDN • PDUs • LAPD- subset of HDLC • Carries Q.931 messages • SAPI – Service Access point identifier • Port used between adjacent layers • TEI – Terminal Equipment Identifier • Identifies one or several TEs

  17. ISDN • PDUs • LAPD- • SAPI+TEI = DLCI = Data link connection identifier

  18. ISDN • PDUs • Q.931 – signaling protocol • Four categories • Establishment • Tear Down • Information phase • Miscellaneous

  19. ISDN • Conclusions • Starting problems – policies • Later problems – upcoming technologies • LAPD and Q.931 – very useful contributions

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