EMM Cause #40 No EPS bearer context activated介绍

EMM Cause #40 No EPS bearer context activated出现在TAU reject或者EMM_Detach_Request场景。

3GPP TS 24.301  5.5.3.2.5

The UE shall deactivate all the EPS bearer contexts locally, if any, and shall enter the state EMM-DEREGISTERED.NORMAL-SERVICE. If the rejected request was not for initiating a PDN connection for emergency bearer services, the UE shall perform a new attach procedure.

NOTE7: User interaction is necessary in some cases when the UE cannot re-activate the EPS bearer(s) automatically.

3GPP主要描述了以下几种场景

1.非紧急呼叫场景，针对reject request#40. 终端deactive所有EPS承载，再重新attach;

2.Attach失败,原因为cause#40情况下，终端可以进行重试；

3.紧急呼叫场景，回落到2/3G完成紧急呼叫；

针对上述几种场景，Log参考如下

1.  TAU reject cause #40时，终端会deactivate所有的承载，再重新attach.

[MS->NW] EMM_Tracking_Area_Update_Request(EPS update type="EMM_UPDATE_TYPE_COMBINED_TAU", active