3.7.5.3 Maintain MSRTC or PIDF Subscriber List Entry

The subscriber list is described in section 2.2.2.6, and specified in section 3.6.

When the incoming SUBSCRIBE request is MSRTC or PIDF, as opposed to category SUBSCRIBE as explained in preceding sections, the subscriber list-related call flow does not change. These subscriptions cause subscribers to be inserted into the publisher's subscriber list if they are not already present there. The main difference is that MSRTC and PIDF subscriptions do not have the "context" concept, which gives category subscribers control over getting themselves into the publisher's subscriber list. Because of this difference, removal of a SubscriberEntry when the acknowledged attribute is "true" is not possible in the case of MSRTC and PIDF subscriptions. The server MUST NOT remove the subscriber entries for these subscriptions. Therefore, even when MSRTC and PIDF subscribers are acknowledged through a setSubscriber request, they are always kept in the subscriber list with the acknowledged attribute value set to "true".