8.3 RAB Release Request

25.4133GPPRelease 17TSUTRAN Iu interface Radio Access Network Application Part (RANAP) signalling

8.3.1 General

The purpose of the RAB Release Request procedure is to enable the UTRAN to request the release of one or several radio access bearers. The procedure uses connection oriented signalling.

8.3.2 Successful Operation

Figure 2: RAB Release Request procedure. Successful operation.

The RNC initiates the procedure by generating a RAB RELEASE REQUEST message towards the CN. The RABs To Be Released IE shall indicate the list of RABs requested to release and the Cause IE associated to each RAB shall indicate the reason for the release, e.g. "RAB pre-empted", "Release due to UTRAN Generated Reason", "Radio Connection With UE Lost".

The RNC shall indicate the Cause IE set to "GTP Resources Unavailable" for the reasons specified in TS 23.007 [53].

Upon reception of the RAB RELEASE REQUEST message, the CN should normally initiate the appropriate release procedure for the RABs identified in the RAB RELEASE REQUEST message as defined below. It is up to the CN to decide how to react to the request.

Interaction with Iu Release Command:

If no RABs will remain according to the RAB RELEASE REQUEST message, the CN should initiate the Iu Release procedure if it does not want to keep the Iu signalling connection. The cause value to use is "No Remaining RAB".

Interaction with RAB Assignment (release RAB):

If the CN decides to release some or all indicated RABs, the CN should invoke the RAB Assignment procedure (release RAB) to this effect.

8.3.3 Abnormal Conditions

Not applicable.