Nortel Networks NN10029-111 manual Instant Messaging, Presence

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For more information and the procedure for setting up Instant Message notifications to emergency numbers, see the SIP Provisioning Client User Guide.

Instant Messaging

Instant Messages are routed in parallel only to a subscriber's dynamically registered routes (see “Registration—static and dynamic” on page 24). This is in contrast to session initiation requests, which are subject to CPL routing logic. Upon receipt of an instant message, a client may respond back to the address supplied in the Contact header. This ensures that the response is sent back to the same client device that originally sent the message.

Presence

When a user initially registers, by default their presence status is set to “on-line” in the SIP registration message. Users subscribe to watch the status of other users, and to coordinate the status of their own devices. This information is maintained in an in-memory table on the SIP Application Module (Presence software). The information that is stored in this table includes:

•the user to be watched

•the party requesting the subscription

•the correlation information identifying that particular subscription request

•contact information regarding where to send the notifications that are generated as a result of the subscription being active

When a user changes their presence (for example, to Busy), a registration message is automatically sent to the SIP Application Module.

The SIP Application Module then checks its in-memory table to see what their previous presence state was. If the update causes a material change in their presence state, the SIP Application Module looks up which users need to be notified of the change (also in memory). This is done by sending a Notify message to each user at every contact contained in the table. For more information, refer to the MCP SIP Presence Basics document.

Voicemail server interoperability and MWI

In order to accomplish voicemail server interoperability and MWI (message waiting indication) notification, the SIP Application Module

NN10029-111 Standard MCP 1.1 FP1 (02.02) April 2003 Copyright © 2003, Nortel Networks