Q. Explain about Address Structure?

Address Structure: ISDN address structure is illustrated in figure. ISDN number part has a maximum of 15 digits and ISDN sub address part a maximum of 40 digits. National destination code is like an area code in telephony network and is of variable length. ISDN subscriber number is the one normally listed in the directories. It is number to be dialed to reach a subscriber in same numbering area. An ISDN number is a unique worldwide address and unambiguously identifies an end point connection. This end point can be:

1. Single S or T reference point,

2. One to many T reference points at the same site

3. One of many S reference points using direct inward dialing feature.

A single S or T reference point can also be addressed by multiple ISDN numbers. This feature is normally used in internetworking.