"EPS Session Management (ESM)

## 定义 / Definition

### English Protocol for managing EPS bearers in LTE networks. ESM handles EPS bearer establishment, modification, and release, as well as PDN connectivity procedures.

### 中文 LTE网络中管理EPS承载的协议。ESM处理EPS承载的建立、修改和释放，以及PDN连接流程。

## EPS 承载 / EPS Bearer

Default Bearer + Dedicated Bearer
    (默认承载)      (专用承载)

## ESM 流程 / ESM Procedures

流程英文中文 ------------------ PDN ConnectivityEstablish PDN connection建立PDN连接 Bearer Resource AllocationRequest dedicated bearer请求专用承载 Bearer ModificationModify QoS修改QoS Bearer ReleaseRelease bearer释放承载

## 消息 / Messages

消息方向描述 ------------------ ACTIVATE DEFAULT EPS BEARER CONTEXT REQUESTNetwork → UE激活默认承载 ACTIVATE DEFAULT EPS BEARER CONTEXT ACCEPTUE → Network接受默认承载 ACTIVATE DEDICATED EPS BEARER CONTEXT REQUESTNetwork → UE激活专用承载

## 交叉引用 / Cross References

- TS 24.301 - ESM specification - TS 23.401 - EPS architecture - EMM - Session Management