The SIP NOTIFY method is used to notify a SIP node (also
known as an end point) about an event change or changes to a node
that the SIP application had earlier requested notification about
through an earlier SUBSCRIBE request. In the case of IBM® XDMS,
the NOTIFY is sent when a change is made to an XCAP document that
has been subscribed to. The NOTIFY API uses the information to generate
an xcap-diff document and send the SIP NOTIFY request to the specified
end point.
Items that trigger a NOTIFY response include:
- A 200 class response to a SUBSCRIBE request
will generate a NOTIFY response to the requester with the duration
of the initial connection (unless the request is being refreshed).
If the response is not a 200 class response no
NOTIFY will be sent.
- When a document is modified.
If a
481 Subscription does not exist response
is received from a NOTIFY request the subscription will be cancelled.
Subscription-State headers provided in the NOTIFY requests include
the following:
- ACTIVE: indicates that the subscription has been accepted.
- TERMINATED: the subscription is not active. A reason tag
will be included with the following information:
- Timeout: The subscription expired or was cancelled.
- Noresource: The document which was subscribed to has been
deleted.