关于S1-MME接口中的eNB UE S1AP ID和MME UE S1AP ID

wenliu

主要从功能上看，单独一个ID就足够eNobdeB,MME区分UE了。

不过站在UE的角度上看， 它在S1 接口的链接必然有两部分组成。一个是给eNodeb用，一个给MME用。
不过规范上上直接规定了：

UE-associated signalling: When S1-AP messages associated to one UE uses the UE-associated logical S1-connection for association of the message to the UE in eNB and EPC.
UE-associated logical S1-connection: The UE-associated logical S1-connection uses the identities MME UE S1AP ID and eNB UE S1AP ID according to definition in TS 23.401 [11]. For a received UE associated S1-AP message the MME identifies the associated UE based on the MME UE S1AP ID IE and the eNB identifies the associated UE based on the eNB UE S1AP ID IE. The UE-associated logical S1-connection may exist before the S1 UE context is setup in eNB.