ISDN

1
ISDN
2
Chapter Twenty Seven Objectives

• Describe ISDN
• What does ISDN really mean to the
  telecommunications industry?
• Why was ISDN initially developed?
• Describe various services available in ISDN
  networking
• Explain why people feel that ISDN was too little
  too late in the USA

3
Integrated Services Digital Network

• A mix of current and future services

4
Integrated Services Digital Network

• CCITT (ITU) reference model

5
Integrated Services Digital Network

• Basic Rate Interface (BRI)

6
Integrated Services Digital Network

• Primary Rate Interface (PRI)

7
Integrated Services Digital Network

• HDLC frame format for LAP-D signaling

8
Integrated Services Digital Network

• Q.931 signaling establishes physical connection
  to X.25 packet handler

9
Integrated Services Digital Network

• Voice call setup in subsecond times

10
Integrated Services Digital Network

• User can shift to 128 Kbps

11
Integrated Services Digital Network

• ISDN protocols compared to ISO

12
Integrated Services Digital Network

• Central Office can support modem pooling with
  non-ISDN terminals

13
Integrated Services Digital Network

• ISDN carrier can provide call processing and
  intelligent network architecture

14
Integrated Services Digital Network

• LEC-to-IEC handoff remote areas served from LEC

15
Integrated Services Digital Network

• At IEC network, 384 to 1,536 Kbps can be accessed
  via digital cross-connect (DCS)

16
Integrated Services Digital Network

• Through PBX, full range of non-voice services.
  PBX to CO via PRI

17
Integrated Services Digital Network

• Various bandwidth requirements thru multirate
  ISDN in a PBX or mux

18
Integrated Services Digital Network

• Actual throughput on BRI is 192 Kbps, only 144
  Kbps each direction available

19
Integrated Services Digital Network

• PRI format T1 at 23 B D and 8 kbps framing or
  E1 at 30 B D

20
Integrated Services Digital Network