Non-Access-Stratum (NAS) protocol for Evolved Packet System (EPS)
红烧三文鱼1. 概述
非接入层（NAS）是UE与MME之间的Uu无线接口的控制面的最高层。主要功能有：
1）对UE移动性的支持
2）对在UE和数据报网关之间建立和保持IP连接的会话管理程序的支持
2. EMM协议
体育训练计划2.1. EMM流程种类
1）EMM常规流程
- GUTI reallocation;
一晚上- authentication;
笛子指法-
离职信模板 curity mode control;
下完这场雨后弦
- identification;
- EMM information.
2）EMM特殊流程
- attach and combined attach.车辆修理
- attach.
- detach and combined detach.
笋菜- normal tracking area updating and combined tracking area updating (S1 mode only);
- periodic tracking area updating (S1 mode only).
3）EMM连接管理流程（S1 mode only）
- rvice request.
- paging procedure.
- transport of NAS messages;
- generic transport of NAS messages.
2.2. EMM common procedures
GUTI reallocation procedure:
allocate a GUTI and optionally to provide a new TAI list to a particular UE.
Authentication procedure:
provide mutual authentication between the ur and the network and to agree on a key KASME
Security mode control procedure:
take an EPS curity context into u, and initiali and start NAS signalling curity between the UE and the MME with the corresponding EPS NAS keys and EPS curity algorithms
Identification procedure:
request a particular UE to provide specific identification parameters, e.g. the International Mobile Subscriber Identity (IMSI) or the International Mobile Equipment Identity (IMEI)
EMM information procedure:
allow the network to provide information to the UE.
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2.3. EMM specific procedures
Attach procedure：
attach to an EPC for packet rvices in EPS
Detach procedure：
is ud:
- by the UE to detach for EPS rvices only;
- by the UE to disconnect from the last PDN it is connected to;
- by the UE in CS/PS mode 1 or CS/PS mode 2 of operation to detach for both EPS rvices and non-EPS rvices or for non-EPS rvices only via a combined detach procedure;
