UTMS RAU流程整理
相关知识点:
第一步,MS通过比较小区标识和自身存储的小区标识是否一致,来确定是否进入新小区; 第二步,MS通过比较MM存储的RAI和网络中收到的RAI是否一致,来确定RAU是否完成。
MS如何获取到小区标识和RAI信息?
情况1:RRC连接状态,服务RNC通过RRC层的“MM消息”来通知MS RAI和小区标识; 情况2:RRC空闲状态,MS通过RRC层的系统广播信息获得RAI和小区标识。
场景:
1.MS处于PMM-CONNECTED状态,或者SGSN内的路由区更新,并且MS处于PMM-CONNECTED状态(会触发下图中信令3,4,这个过程目的是得到PDP上下文序列号),SRNS收到请求会停止发送下行PDUs到MS。 信令流程:(1,3,4,6,8,9,21,22)
PS:我理解,这种情况下就是MS有业务在进行,RAU流程会涉及到与SRNs进行交互的一些信令。
2.SGSN间的路由更新,MS处于PMM-IDLE状态(触发下图中信令2)。
信令流程:(1,2,5,6,7,11,12,13,14,17,18,19,20,21,22)
总体信令流程:
1.Routeing Area Update Request
msinfo8.SRNS DATA Forward Command
11.Update PDP Context Request
12.Update PDP Context Response
17.Cancel Location Ack
16.Iu Release Complete
18.Insert Subscriber Data
19.Insert Subscriber Data Ack
21.Routeing Area Update Accept
20.Update Location Ack
22.Routeing Area Update Complete
信令中消息的关键字段:
1.Routeing Area Update Request:PTMSI;old RAI;old PTMSI Signature;Update Type(路由区更新触发;周期性路由区更新定时器触发;RA/LA联合更新;附带IMSI附着的RA/LA联合附着);follow on request;Classmark;DRX Parameters;MS Network capability
2.SGSN Context Request:MS的P-TMSI和P-TMSI Signature
4.SRNS Context Response:IMSI, GTPSNDs, GTPSNUs, PDCPSNUs
5.SGSN Context Response:MM Context, PDP Contexts, Negotiated Evolved ARP
7.SGSN Context ACK:作用于SGSN间的RAU,旧SGSN收到ACK后会在上下文中标识GGSN,HLR中消息非法
8.SRNS DATA Forward Command:RAB ID, Transport Layer Address, Iu Transport Association
9.Forward Packets:GTP PDUs
11.Update PDP Context Request:new SGSN Address, QoS Negotiated, Negotiated Evolved ARP, Tunnel Endpoint Identifier, serving network identity, CGI/SAI, RAT type, MS Info Change Reporting support indication, NRSN
12.Update PDP Context Response:Tunnel Endpoint Identifier, Prohibit Payload Compression, APN Restriction, MS Info Change Reporting Action, CSG Information Reporting Action, BCM, Negotiated Evolved ARP
13.Update Location:SGSN Number, SGSN Address, IMSI, IMEISV, Homogenous Support of IMS Over PS Sessions
14.Cancel Location:IMSI, Cancellation Type
18.Insert Subscriber Data:IMSI, subscription data
19.Insert Subscriber Data Ack:IMSI
20.Update Location Ack:IMSI
21.Routeing Area Update Accept:PTMSI, VLR TMSI, PTMSI Signature, IMS voice over PS Session Supported Indication, Emergency Service Support