Nortel Networks NN43001-314 - Manual (Page 52)

52 Overview
Local Mode at the Branch Office, the MG 1000B telephones remain in Local
Mode, displaying aServer Unreachable (1) message and receives all call
processing services from the CP PM in the MG 1000B Core.
MG 1000B IP Phones in Normal Mode remain registered with the main office
when the Primary NRS fails and no Alternate or Failsafe NRS is available.
They can call any main office telephone or IP Phones in Normal Mode in
other branch offices. However, they cannot call any MG 1000B digital
telephones, analog (500/2500-type) telephones, or any external number
through the MG 1000B trunks in the normal way, because the Virtual Trunks
are not available. (MG 1000B digital or analog (500/2500-type) telephones
are accessible if alternate routing is available through the PSTN.) The user
has the option of staying in Normal Mode, or 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 Phones, digital telephones, and
analog (500/2500-type) telephones at the Branch Office. They can also be
used to make outgoing PSTN calls as usual.
You must plan for, and obtain, the Primary and optional Alternate NRS
addresses for installing the Branch Office feature software. Determine the
NRS role, that is, the Alternate or Failsafe configuration, for the MG 1000B
Signaling Server.
Nortel recommends that the NRS in the MG 1000B be configured as a
Failsafe NRS, unless it is already acting as the Primary or Alternate NRS.
If the MG 1000B IP Phones go into Local Mode, they can use the MG
1000B NRS services.
For CallPilot Mini and CallPilot 201i applications, a Message Waiting
Indication (MWI) does not survive a Mode change (Normal to Local or Local
to Normal). The message itself is preserved, but the lamp indicator may not
be lit after the Mode change.
Active Call Failover
The Active Call Failover (ACF) feature for IP Phones allows active IP calls to
survive the following failures:
• IP/IP calls and IP/TDM calls survive signaling path TLAN subnet failures.
• IP and IP/TDM calls survive Signaling Server restarts.
• IP and IP/TDM calls survive LTPS ELAN subnet failures.
• IP calls survive a Call Server cold start and Call Server failures in
system configuration with a redundant Call Server.
ATTENTION
All IP Phones excluding Phase 1/0 support Active Call Failover.
Nortel Communication Server 1000
Branch Office Installation and Commissioning
NN43001-314 01.02 Standard
Release 5.0 20 June 2007
Copyright © 2007, Nortel Networks
.