Nortel Networks NN43001-314 - Manual (Page 130)

130 Alternative Call Routing for Network Bandwidth Management
The ALTPrefix applies to the zone in which the call originates. There is one
ALTPrefix for each zone that requires alternate routing.
All Call Servers must be able to translate the ALTPrefixes for all zones that
require Alternative Call Routing for NBWM.
How Alternative Call Routing for NBWM works
When a user dials a station-to-station call between two different zones (that
is, the calling and called telephones are not located in the same geographic
area) and the bandwidth limit has been reached, then the Alternative Call
Routing feature is invoked.
The following steps occur in Alternative Call Routing scenarios.
Call from Branch Office telephone in Normal Mode
1. The interzone station-to-station call is attempted. There is insufficient
bandwidth available to make the call.
2. The main office inserts the ALTPrefix associated with the originator’s
zone (the Branch Office in this case) before the dialed digits.
3. The main office uses Coordinated Dialing Plan (CDP) or Vacant Number
Routing (VNR) to route the call to a virtual trunk.
4. A request is made to the NRS to determine the endpoint. The NRS
returns the Branch Office address as the endpoint.
5. The call is routed on the virtual trunk to the Branch Office.
6. The Branch Office treats the ALTPrefix as a steering code. The
Branch Office determines the Route List Index (RLI) and uses a
Digit Manipulation Index (DMI) to change the dialed number into a
PSTN/MCDN format number.
7. The call is routed over the PSTN/MCDN trunks to the telephone at the
main office or other Branch Office.
Call from main office telephone to Branch Office telephone
1. The interzone station-to-station call is attempted. There is insufficient
bandwidth available to make the call.
2. The main office inserts the ALTPrefix associated with the originator’s
zone (the main office in this case) before the dialed digits.
3. The main office uses CDP and recognizes the ALTPrefix as a steering
code.
4. The main office determines the RLI and uses a DMI to change the
dialed number into a PSTN/MCDN format number.
Nortel Communication Server 1000
Branch Office Installation and Commissioning
NN43001-314 01.02 Standard
Release 5.0 20 June 2007
Copyright © 2007, Nortel Networks
.