User's Manual

when it detects that the current server is unreachable. The IP Deskphone stays with
the new server, not switching back unless the new server fails.
2. In Survivable Branch mode, the IP Deskphone is configured with IP addresses for
a primary server and a secondary server. When the primary server is unreachable,
the IP Deskphone switches to the secondary server. The IP Deskphone continues
to monitor the primary server and switches back to the primary server as soon as
it is back on line.
To enable this functionality, the following configuration parameter is introduced:
FAIL_BACK_TO_PRIMARY YES/NO (default is NO)
Note:
Before falling back to the primary server, the IP Deskphone checks if there is an active call
and if there is an active call, switching is deferred until the call is terminated.
Important:
Multiple user login is not supported in failover mode.
DHCP enhancements
Configurable DHCP discovery and timeout:
Some IP Deskphones operate in PoE environments where power is applied to the IP
Deskphones and the network at the same time. The DHCP server may not be ready before
the IP Deskphone times out. SIP 4.3 provides the ability to configure the number of times the
IP Deskphone can attempt to contact the DHCP server and the time interval between
attempts.
Two new parameters are introduced.
DHCP_NUMBER_OF_RETRIES. The default value is 4.
DHCP_INITIAL_TIMEOUT. The default value is 4 seconds).
If the DHCP server does not respond, the IP Deskphone sends several requests one after
another in different timeout intervals, based on the formula “timeout[i]=2* timeout[i-1] +- 1sec”,
where :’ i’ is number of retries and timeout[0]= DHCP_INITIAL_TIMEOUT.
The maximum timeout between Discovery requests cannot be greater than 64 seconds. If the
value of the next timeout becomes greater than 64 seconds, the DHCP client stops increasing
the timeout interval and keeps the timeout value of 64 seconds.
Cached IP address:
New in this release
10 SIP Software for Avaya 1100 Series IP Deskphones-Administration November 2012
Comments? [e-mail]