• Recognise the issues and impacts of using dial up networks.
• Describe ISDN.
• Describe ISDN signalling in voice and data environments.
• Configure a Cisco router to use ISDN.

Introduction
Dialup connectivity vs. leased lines vs. packet switched networks. ISDN offerings, services, benefits vs. modems.

ISDN architectures
Use of ISDN by routers, Dial up, top up, backup. Internet access, PCs and ISDN.

BRI and PRI
ISDN switches, B channels, D channel, ISDN functions and reference points, NT1, NT2, TE1, TE2, Terminal adapters, R,S,T,U interfaces, ISDN standards.

PPP
Encapsulation, PPP services, PAP and CHAP, Multilink PPP, BACP.

ISDN and the seven layer model
B channel layers versus D channel layers, the I standards, Q.921, Q.931.

Configuration issues for ISDN
E.164 addressing and IP addresses, ensuring only the correct traffic brings up the ISDN line.

ISDN services
Bearer services, teleservices, supplementary services, MSN, sub addressing, CLI…