【资料名称】：单信令导致掉话(掉话投诉)

【资料作者】：WU

【资料日期】：2012-08-01

【资料语言】：中文

【资料格式】：DOC

【资料目录和简介】：

在3GPP的TS25.413协议中，对于IU释放的发起原因，提到一点：在没有RAB、且Iu连接无数据情况下，CN应该发起Iu释放（The Iu release procedure should also be initiated when there is a period of Iu signalling inactivity with no existing RAB.）
8.5Iu Release
8.5.1General
The purpose of the Iu Release procedure is to enable the CN to release an Iu connection for a particular UE and all UTRAN resources related only to that Iu connection. The procedure uses connection oriented signalling.
The Iu Release procedure can be initiated for at least the following reasons:
- Completion of transaction between the UE and the CN.
- UTRAN-generated reasons, e.g. reception of an IU RELEASE REQUEST message.
- Completion of successful relocation of SRNS.
- Cancellation of relocation after successful completion of a Relocation Resource Allocation procedure.
- Detection of two Iu connections in the same domain toward one UE.
The Iu release procedure should also be initiated when there is a period of Iu signalling inactivity with no existing RAB.
对此，已经确定由于交换在RAB释放后，未及时释放IU口，导致单信令出现跨RNC失败出现掉话