Nortel Networks NN43001-121 manual Branch Office redundancy MG 1000B/SRG

Remote Call Control with SIP CTI 79

•After an event occurs that causes the IP Phones to register to a server other than the Front End server (and then to return to the Front End server), the Office Communicator 2007 client does not automatically follow the IP Phone registration. To direct the TR/87 sessions back to the TR/87 FE that corresponds to the home TPS, take one of the following actions:

—Users must log out and log back onto the TR/87 client (for example, Office Communicator 2007) to force the previous SIP dialog to terminate so that a new dialog can be established, which NRS redirects to the correct TR/87 FE.

—An administrator issues the SIPCTIStop all command on the Signaling Server on which the TR/87 sessions currently reside to terminate the SIP dialogs. This forces the clients to send another association request (for example, SIP INVITE), which the NRS redirects to the correct TR/87 FE, as depicted in Table 16 "SIPCTIStop all command" (page 79).

Table 16

SIPCTIStop all command

Command	Description
SIPCTIStop all	De-acquire all AST DNs and terminate all TR/87 SIP sessions.

Branch Office redundancy (MG 1000B/SRG)

Branch Office scenarios can be supported; however, SIP CTI support and Telephony Gateway and Services are available for Branch User IP Phones in Local mode (registered in the Branch Office) only when the following conditions are met:

• The Branch Office has SIP CTI and Telephony Gateway and Services enabled and has a Signaling Server dedicated to each branch.

• The network dialing plan is a Coordinated Dialing Plan (CDP).

• The IP Phone (Branch User) has the same domain name configured in both the Main Office and Branch Office.

• The Branch Office has access to the NRS and Office Communications Server (OCS). If access is disrupted, failure cases may not be supported if the NRS and OCS are located in close proximity to the Main Office, which is no longer available. For example, when the WAN link to the Main Office is down, the NRS and OCS are out-of-service.

• The SIP Gateway in the Main Office is out -of-service (in which case the SIP Gateway in the Branch Office is used).

Nortel Communication Server 1000

Nortel Converged Office Fundamentals — Microsoft Office Communications Server 2007

NN43001-121 01.03 Standard

Release 5.0 30 April 2008

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