Share via

3.4.5.1 Receiving a Piggyback Notification in a 200 OK

  • Article

If the server supports piggyback NOTIFY requests, it sends the content that is typically placed in the first NOTIFY request within the 200 OK SIP response to the SUBSCRIBE request. The content of the 200 OK response to the SUBSCRIBE request matches the content type that the client specified in the Accept header of the SUBSCRIBE. The server signals support for the piggyback extension in a similar header in the 200 OK response to the SUBSCRIBE.

 Supported: ms-piggyback-first-notify

When the client receives the 200 OK SIP response to the SUBSCRIBE request, it SHOULD check whether the preceding header is included in the 200 OK. If it is, the client MAY set the PiggybackNotifyEnabled flag to true, handle this 200 OK response as though it had received a separate NOTIFY request, and parse the content to obtain the presence information.

The first NOTIFY request that the server sends is then delayed until an actual change in presence occurs.