Isdn Call Connection Limitation - Nortel ICS Install Manual

154 / Private networking using PRI SL-1

ISDN Call Connection Limitation

The ICCL feature piggybacks on the call initiation request and
acts as a check at transit PBX points to prevent misconfigured
routes or calls with errors from blocking channels.
This feature adds a transit/tandem counter to a call setup
message. This counter is compared at each transit PBX with a
value programmed into the transit PBX, in a range from 0 to
31. If the call setup counter is higher than the PBX value, the
call will be blocked at the PBX and cleared back to the
network. This prevents calls from creating loops that tie up
lines.
Norstar configurations:
• Setting ICCL
1. With the display showing System prgming press
' until the display shows NetworkServices.
2. Press ≠ until MCDN displays.
3. Press ≠. NetwkICCL: displays.
4. Press CHANGE to choose either Y (yes) or N (no)
Under Hardware, define Maximum transits for the card.
•
The diagram below demonstrates how a call might loop
through a network if the system is not set up with the ICCL
feature.
Modular ICS 7.1 Installer Guide N0130943 02