8.8 Relocation Detect

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

8.8.1 General

The purpose of the Relocation Detect procedure is to indicate to the CN the detection by the RNC of an SRNS relocation execution. The procedure shall be co-ordinated over all Iu signalling connections existing for the UE. The procedure uses connection-oriented signalling.

8.8.2 Successful Operation

Figure 9: Relocation Detect procedure: Successful operation.

The target RNC shall send a RELOCATION DETECT message to the CN when a relocation execution trigger is received.

If the type of relocation of SRNS is "UE involved in relocation of SRNS", the relocation execution trigger may be received either from the Uu interface or as an implementation option from the Iur interface. If the type of relocation of SRNS is "UE not involved in relocation of SRNS", the relocation execution trigger is received from the Iur interface.

When the RELOCATION DETECT message is sent, the target RNC shall start SRNC operation.

Upon reception of the RELOCATION DETECT message, the CN may switch the user plane from the source RNC to the target RNC.

8.8.3 Abnormal Conditions

Interactions with Relocation Complete procedure:

If the RELOCATION COMPLETE message is received by the CN before the reception of the RELOCATION DETECT message, the CN shall handle the RELOCATION COMPLETE message normally.

8.8.4 Co-ordination of Two Iu Signalling Connections

When the Relocation Detect procedure is to be initiated by the target RNC, the target RNC shall initiate the Relocation Detect procedure on all Iu signalling connections existing for the UE between the target RNC and the CN.