Survivability 53
ACF mode
The ACFfeature for IP Phones enables an IP Phone to reregister in the ACF
mode during a supported system failure.
The ACF mode preserves the following:
•active media session
•LED states of the Mute, Handsfree, and Headset keys
•DRAM content
All other elements (the feature keys,soft keys and text areas) are retained
until the user presses a key or the connection with the Call Server is
resumed. If the user presses a key during the failover, the display area is
cleared and a localized "Server Unreachable" message is displayed.
TheIP Phone uses this newmode ofreregistration only when theCall Ser ver
explicitly tells the IP Phone to do so. IP Phones clear all call information
when registering to a Call Server or LTPSthat does not support the feature.
For further information on Active Call Failure, referto IP Line Fundamentals
(NN43100-500).
Configuring S2 IP Address to point to the main office TPS
This configuration programs the S1 IP address parameteron the MG 1000B
IP Phone as the Node IP of the Branch Office, and S2 as the Node IP of the
main office (normally, S2 would be set to NULL).
This configuration provides better resiliency when an MG 1000B IP Phone
cannot access the Branch Office overthe local LAN or WAN (due to network
problems, forexample), but can access the main office. In this case, the IP
Phone tries to register directly with the main office.
This configuration is supported only under the following conditions:
•Relaxed node ID checking is in operationbetween the Branch Office
and the main office. Four digits are configured on the TPS for the Node
ID,and the first three digits of that Node ID make up the Node ID on the
IP Phone. For example, 5701 is configured on the main office TPS and
5702 on the MG 1000B TPS,where 570 is the Node ID on the IP Phone.
•The same TN is programmed on the main office and Branch Office for
the IP Phone.
•The main office is a CS 1000E system.
The IP Softphone 2050 does not support S2 Addresses. However, the IP
Softphone 2050v2 does have the ability to configure S2.
Nortel Communication Server 1000
Branch Office Installation and Commissioning
NN43001-314 01.02 Standard
Release 5.0 20 June 2007
Copyright© 2007, Nor tel Networks
.