What happens if I don’t use the radio functions of myterminal for a long period, typically 10 or 20seconds, for example, because I’m not looking at a Website or I don’t have an application sending data to thenetwork or receiving data?如果我长时间不使用终端的无线电功能会发生什么情况，例如10秒或20秒，因为我不是在看网站，或者我没有应用程序将数据发送到 网络还是接收数据？
We know the answer: we will switch from the stateECM-Connected (with a radio connection) to the stateECM-IDLE (where there is no radio connection).我们知道答案：我们将从状态ECM-Connected（使用无线电连接）切换到状态ECM-IDLE（没有无线电连接）。
Here’s the initialstate we’re talking about.这是我们谈论的初始状态。
The terminal has a set of tunnels and connectionsestablished, including the radio connection,it is in ECM-Connected state andthe MME has memorized ECM-Connected state,with regards to the terminal we’re discussing.终端具有一组隧道和连接建立，包括无线连接，它处于ECM连接状态，MME已记忆ECM-Connected状态，关于我们正在讨论的终端。
Here, we see the release procedure.在这里，我们看到了发布程序。
We show bearers that have been established.我们展示了已经建立的承载者。
The terminal is inactive, in other words, there hasn’tbeen a transmission of user packets for a certain time.终端是不活动的，换句话说，在一定时间内没有用户分组的传输。
At the end of this time, typically ten, twenty or thirtyseconds, the eNodeB sends an S1-AP message, requestingthe release of the context.在此时间结束时，通常为十秒，二十或三十秒，eNodeB发送S1-AP消息，请求释放上下文。
It will indicate the reason: user inactivity.它将指出原因：用户不活动。
The MME then sends a GTP control message, requesting therelease of the tunnel between the SGWand the eNodeB.然后，MME发送GTP控制消息，请求释放SGW和eNodeB之间的隧道。
The SGW processes the request and respondspositively to the MME, it means that the releasehas been done and the MME informsthe eNodeB that the release is to be done on its side.SGW处理请求并对MME做出积极响应，这意味着已经完成了发布，并且MME通知eNodeB将在其侧进行释放。
The eNodeB informs the terminal that the connection has been released.eNodeB通知终端已释放连接。
The terminal returns to standby mode.终端返回待机模式。
If the user is playing a game and it’s a game that doesnot generate radio exchanges, the terminal remains active.如果用户正在玩游戏并且它是不产生无线电交换的游戏，则终端保持活动。
however, from a radio point of view, it is inactive.但是，从无线电的角度来看，它是不活跃的。
It considers that the RNTI is nolonger allocated, so it can no longer use theRNTI, and the eNodeB releases the radioconnection and the RNTI.它认为RNTI不再被分配，因此它不再使用RNTI，eNodeB释放无线连接和RNTI。
Once this is done, the eNodeB responds to theMME to indicate that release has been fully carried out.完成此操作后，eNodeB会响应MME以指示已完全执行释放。
At the end of this procedure, the terminal and the MMEfor this terminal return to the state ECM-IDLE.在该过程结束时，该终端的终端和MME返回到状态ECM-IDLE。
On the other hand, the terminal keepsits IP address, so it remainsin the state EMM-Registered.另一方面，终端保持其IP地址，因此它保持在EMM-Registered状态。
So, we have two types of states: ECM states and EMM states.因此，我们有两种状态：ECM状态和EMM状态。
In EMM-Deregistered state, the terminaldoes not exist, from the point of view of the network, soit is necessarily in ECM-IDLE state.在EMM-Deregistered状态中，从网络的角度来看，终端不存在，因此它必须处于ECM-IDLE状态。
It is disconnected from the network and doesnot have an IP address.它与网络断开连接，没有IP地址。
In EMM-Registered and ECM-Connected, the terminal is connected to the network:it has an IP address and an RNTI, its location is known down to the cell level by the MMEand all the tunnels and the connectionshave been established.在EMM-Registered和ECM-Connected中，终端连接到网络：它具有IP地址和RNTI，其位置在MME下已知到小区级别，并且已建立所有隧道和连接。
In EMM-Registered and ECM-IDLE (from the point of viewof the applications and the user), it is still connected.在EMM-Registered和ECM-IDLE中（从应用程序和用户的角度来看），它仍然是连接的。
The terminal appears to be connected to the network:it has its IP address, but it does nothave an RNTI allocated, and there is no tunnel orconnection leading from the eNodeB.终端似乎连接到网络：它具有IP地址，但没有分配RNTI，并且没有从eNodeB引出的隧道或连接。
However, the tunnel between the Serving Gatewayand the P Gateway, and the tunnel between the ServingGateway and the MME are maintained.但是，保持服务网关和P网关之间的隧道，以及服务网关和MME之间的隧道。
Why? Because a Serving Gateway manages a large areaand the probability of changing Serving Gateways withinseveral minutes is relatively low.为什么？ 因为服务网关管理大面积，并且在几分钟内更改服务网关的可能性相对较低。
In this state, EMM Registered and ECM-IDLE, the precise celllocation of the UE is not known exactly.在这种状态下，EMM Registered和ECM-IDLE，UE的精确小区位置并不确切。
The network is not too concerned about knowing in exactlywhich cell the terminal is located.网络并不太关心终端确切地知道哪个小区。
So we have the following: when the cell phone iscompletely absent from the network, it is not associatedto a Serving Gateway or P Gateway (I’ve added a few in the diagram).所以我们有以下内容：当手机完全不在网络中时，它不与服务网关或P网关相关联（我在图中添加了一些）。
When it attaches to the network, it changes toEMM-Registered and ECM-Connected,there is an RRCx connection, all tunnels are established.当它连接到网络时，它变为EMM-Registered和ECM-Connected，存在RRCx连接，所有隧道都建立。
When the inactivity timer times out,its state will change to ECM-IDLE, but it willremain in EMM-Registered state, in other words, it keeps the IP address.当不活动定时器超时时，其状态将变为ECM-IDLE，但它将保持EMM-Registered状态，换句话说，它保留IP地址。
转载于:https://www.cnblogs.com/sec875/articles/10039562.html
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