User's Manual

28 Overview

Nortel Networks Confidential

Restart If you want to simply force an immediate manual fail-over,

then you can request a Restart from the Management Console.

For more information, see the Configuration chapter in this document.

OAM&P strategy

The Management Module manages the OAM&P functions for the SIP

Application Module. For additional information, refer to the MCP

Management Module Basics and the MCP System Management

Console Basics documents.

WARNING

The N+M reliability strategy provides a highly

available service environment. The fail-over

mechanisms enable an instance of the SIP

Application Module to survive failure condition(s) by

migrating to a standby server where it can resume

the processing of new sessions.

In such a highly available service environment the

failed instance loses all knowledge of sessions

started before the fail-over event. Therefore, the

stability of these pre-existing sessions cannot be

guaranteed. For example:

Sessions involving SIP clients will survive until the

clients encounter a "no response" or "unknown call"

response to a request on their active session. At that

point the clients will release the session and its

associated media resources.

Sessions involving the MCP SIP PRI Gateway will

survive until there is no response to the SIP PRI

Gateway-generated SIP "ping" to the SIP Application

Module(s) handling the active sessions on the

gateway. If there is no response to the SIP "ping"

then the gateway will tear down the associated call

and recovers its resources.

Also, sessions involving the MCP RTP Media Portal

will not survive a manual fail-over because

intentionally LOCKing the SIP Application Module

initiates the automatic recovery of all resources

(including RTP Media Portal resources) associated

with in-progress sessions.