162 How the Branch Office feature works
Before the Branch Office IP Phone attempts to register with the main office,
the MG 1000B first queries the Primary NRS (NCS) fro the main office for
the Virtual Trunknode IP address to redirect the IP Phone. If the Primary
NRS (NCS) is down or unreachable, the MG 1000B queries the Alternate
NRS, if one is specified. If it receives a positive response, the MG 1000B
is redirected to the specified main office. Otherwise, it neither a Primary
or an Alternate NRS is available, the Branch Office IP Phone remains in
Local Mode, and receives call processing services from the MG 1000B
until communication is reestablished.
If an IP Phone is in Local Mode due to WAN failure, the MG 1000B
tries to communicate with the main office TPS at regular intervals. Once
communication is established with the main office Call Server, the idle
Branch Office IP Phones are automatically redirected and reregistered to
the main office. IP Phones that were busy at the time communication was
reestablished, complete the call in Local Mode, and then reregister with the
main office once the call is complete.
MG 1000 IP Phones in Normal Mode remain registered with the main office
if the Primary NRS fails and no Alternate NRS is available. They can call
any main office telephone or IP Phones in Normal Mode in other branch
offices. However, theycannot call an Branch Office analog (500/2500-type)
telephones, digital telephones, or any external numbers through the MG
1000B trunks because the Virtual Trunks are not available. (MG 1000B
analog [500/2500-type] or digital telephones, are accessible if alternate
routing is available through the PSTN.)
Features supported in Local Mode
In Local Mode, IP Phones receive only those features and tones that are
provisioned on the call server. The features are not necessarily the same in
Normal Mode due to local configuration, or if the Branch Office and main
office are running different software releases or differentser vice levels.
When the Branch Office is running a previous software release, the Local
Mode features are limited to those available in that release. Depending on
what is provisioned, this means that Normal Mode may have more features
than Local Mode.
A user can attempt a Virtual Office Login to an MG 1000B IP Phone from an
MG 1000B IP Phone in Local Mode. If the Virtual Office Login is successful,
the Virtual Office user is registered with either the Branch Office or main
office. A Branch Office in local mode only accepts Coordinated Dialing Plan
(CDP) numbers as Virtual Office user ID’s.
Nortel Communication Server 1000
Branch Office Installation and Commissioning
NN43001-314 01.02 Standard
Release 5.0 20 June2007
Copyright© 2007, Nor tel Networks
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