具体的解释查阅3gpp的36.413规范 >Radio Network Layer >>Radio Network Layer Cause (Unspecified, TX2RELOCOverall Expiry, Successful Handover, Release due to E-UTRAN Generated Reason, Handover Cancelled, Partial Handover, Hando ver Failure In Target EPC/eNB Or Target Syste m, Handover Target not allowed, TS1RELOCoverall Expiry, TS1RELOCprep Expiry, Cell not available, Unknown Target ID, No Radio Resources Available in Target Cell, Unknown or already allocated MME UE S1AP I D, Unknown or already allocated eNB UE S1AP I D, Unknown or inconsistent pair of UE S1AP ID, Handover desirable for radio reasons, Time critical handover, Resource optimisation handover, Reduce load in serving cell, User inactivity, Radio Connection With UE Lost, Load Balanci ng TAU Required, CS Fallback Triggered, UE Not Available For PS Service, Radio resour ces not available, Failure in the Radio Interface Procedure, Invalid QoS combination, Inter-RAT redirectio n, Interaction with other procedure, Unknown E-RAB ID, Multiple E-RAB ID instances, Encrypti on and/or integrity protection algorithms not supported, S1 intra system Handover triggere d, S1 inter system Handover triggered, X2 Ha ndover triggered …, Redirection towards 1xRTT, Not supported QCI value, invalid CSG Id)
>Transport Layer >>Transport Layer Cause ENUMERATED (Transport Resource Unavailable, Unspecified, …)
>NAS >>NAS Cause ENUMERATED (Normal Release, Authentication failure, Detach, Unspecified, …, CSG Subscription Expiry)
>Protoc ol >>Protocol Cause ENUMERATED (Transfer Syntax Error, Abstract Syntax Error (Reject), Abstract Syntax Error (Ignore and Notify), Message not Compatible with Receiver State, Semantic Error, Abstract Syntax Error (Falsely Constructed M essage), Unspecified, …)
>Misc >>Miscellaneous Cause ENUMERATED (Control Processing Overload, Not enough Us er Plane Processing Resources, Hardware Failure, O&M Intervention, Unspecified, Unknown PLMN, …)