24.4103GPPCommunication HOLD (HOLD) PSTN/ISDN simulation servicesNGN Signalling Control ProtocolProtocol specificationRelease 8TISPANTS

A.2.1 RESUME communication without announcement

The following diagram shows how a communication session is resumed using a reINVITE request, note that the same can be achieved by sending an UPDATE request.

Figure A.2.1.1: RESUME communication without announcement to the held user

1. UE-A sends an INVITE to UE-B to resume the session. Resume is done by changing the SDP attribute:

• "a=sendrecv", if the stream was previously a recvonly media stream, or the attribute may be omitted, since sendrecv is the default;
• "a=recvonly", if the stream was previously an inactive media stream.

A.2.2 RESUME communication with announcement

The following diagram shows how a communication session is resumed using a reINVITE request, note that the same can be achieved by sending an UPDATE request.

Figure A.2.2.1: RESUME communication with announcement to the held user

1. UE-A sends an INVITE to UE-B to resume the session. Resume is done by changing the SDP attribute:

• "a=sendrecv", if the stream was previously a recvonly media stream, or the attribute may be omitted, since sendrecv is the default;
• "a=recvonly", if the stream was previously an inactive media stream.

Annex B (informative):
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