Nortel Networks NN43001-314 - Manual (Page 161)

Normal Mode and Local Mode operation 161
An IP Phone at the Branch Office may be in Local Mode for two different
reasons:
• IP Phone may have just booted up
• IP Phone cannot communicate to the main office because of a WAN
failure or a failure of the main office components.
In the event of a WAN failure, the Branch Office IP Phones lose
communication with the main office. This causes the Branch Office IP
Phones to reset and reregister with the Branch Office. The IP Phones then
operate in Local Mode. providing services based on a limited MG 1000B
feature set, which has significant differences from the CS 1000 software.
If the main office Call Server fails and call processing services are provided
by an Alternate Call Server, the Branch Office IP Phone reset and reregister
with the Alternate Call Server and receive call processing services from it.
If no Alternate Call Server is available, the Branch Office IP Phones go to
Local Mode while the MG 1000B attempts to find an Alternate Call Server
by way of the NetConnect Server (NCS).
When the main office Signaling Server fails and an Alternate Signaling
Server is available, the Branch Office IP Phones reset and reregister with
the Branch Office. The MG 1000B will query the NCS for the Alternate
Signaling Server’s IP address. The MG 1000B will redirect the IP Phone
to the Alternate Signaling Server and continue to receive call processing
services from the main office Call Server. If no Alternate Call Server is
available, the Branch Office IP Phones reset and reregister with the MG
1000B in Local Mode.
The user has the option of going to Local Mode manually by resetting the
telephone or using Test Local Mode. In Local Mode, the IP Phones can
make local calls to other IP Phone and analog (500/2500) or digital phones
at the Branch Office. They can also be used to make outgoing PSTN calls
and receive incoming calls as usual.
ATTENTION
IMPORTANT!
When a telephone or trunk in the main office calls an MG 1000B IP Phone in Local
Mode, the call is treated according to the main office call redirection configuration
(such as forwarding to voicemail or continuous ringback).
When an IP Phone at the Branch Office first boots up it attempts to
communicate with the MG 1000B. Once it has established communications
with the MG 1000B, the MG 1000B will redirect the IP Phone to the main
office.
Nortel Communication Server 1000
Branch Office Installation and Commissioning
NN43001-314 01.02 Standard
Release 5.0 20 June 2007
Copyright © 2007, Nortel Networks
.