2.TAU
| 消息序號(hào) | Activity | 為什么要發(fā)送這些請(qǐng)求或命令? | 傳遞的參數(shù) | 重要的參數(shù) | 發(fā)生的條件或情況 | 收到消息的網(wǎng)元會(huì)做哪些事情? | 要注意的一些點(diǎn) | 問題 |
| 2 | TAU Request | UE Core Network Capability, old GUTI, last visited TAI, active flag, EPS bearer status, P?TMSI Signature, additional GUTI, eKSI, NAS sequence number, NAS-MAC, KSI RRC參數(shù):(selected network,old GUMMEI,load reblancing TAU) | old GUTI, P?TMSI Signature; active flag, EPS bearer status; RRC參數(shù):(selected network,old GUMMEI,load reblancing TAU) | 必須 | eNodeB: ???? 1.找MME:根據(jù)selected network+old GUMMEI; ???? 2.如果MME和eNodeB不相連或GUMMEI不可及,或UE指示這個(gè)TAU是由于負(fù)載均衡引起的,則eNodeB選擇MME; | |||
| 3 | TAU Request | complete TAU Request message; ?TAI+ECGI; Selected Network | 必須 | new MME: ?????????? 1.獲取用戶信息:通過old GUTI找到old MME/SGSN | ||||
| 4 | Context Request | 請(qǐng)求用戶信息 | old GUTI, complete TAU Request message, P?TMSI Signature, ?MME Address, UE validated | old GUTI, complete TAU Request message, P?TMSI Signature, ?MME Address, UE validated | 必須 | old MME/SGSN: ????????? 1.驗(yàn)證Context Request的有效性; ????????? 2.啟動(dòng)定時(shí)器 | 啟動(dòng)的timer的作用: 1) 控制old MME/SGSN刪除MM上下文 2) 控制old SGSN刪除Iu連接,Old MME如果有舊的S1連接也需要釋放 3) 控制old MME/SGSN刪除本地承載資源 4) 控制old MME/SGSN刪除到old SGW的承載 | |
| 5 | Context Response | old MME:(ME Identity (if available), MM Context, EPS Bearer Context(s), Serving GW signalling Address and TEID(s), ISR Supported, MS Info Change Reporting Action (if available), UE Core Network Capability, UE Specific DRX Parameters) old S4 SGSN:(MM Context, EPS Bearer Context(s), Serving GW signalling Address and TEID(s), ISR Supported, MS Info Change Reporting Action (if available), UE Core Network Capability, UE Specific DRX Parameters) | 重要參數(shù): 1.EPS Bearer Context(s):包含PDW地址等 2.Serving GW signalling Address and TEID(s) 3.UE Core Network Capability | 如果UE在老的MME中未知 或TAU Request消息完整性檢查失敗, 老的MME返回一個(gè)合適的錯(cuò)誤原因(error cause) | ||||
| 6 | Authentication /Security | 需要鑒權(quán)或安全功能 | ?1.如果TAU Request完整性檢查失敗,則鑒權(quán)是必須的。 2.如果需要分配GUTI并且網(wǎng)絡(luò)支持加密,則NAS消息應(yīng)被加密。 | 鑒權(quán)結(jié)果: 1.失敗: ????? TAU更新應(yīng)被拒絕,并且新的MME發(fā)送一個(gè)拒絕指示給老的MME/S4 SGSN。老的MME/S4 SGSN應(yīng)繼續(xù)就像從沒收到過Identification and Context Request。 2.成功: ?????? 繼續(xù)。此時(shí)new MME已經(jīng)有了用戶的信息,new MME是否要換SGW。 | new MME這幾種情況下?lián)QSGW: 1.S-GW不能繼續(xù)服務(wù)UE時(shí), 2.新的S-GW期望更久地服務(wù)UE 3.有更優(yōu)的UE到PDN-GW的通道情況下 4.新的S-GW能和PDN-GW在同一節(jié)點(diǎn)上 | |||
| 7 | Context Acknowledge | 向old MME/SGSN確認(rèn)上下文收到,并指示SGW是否變化 | Serving GW change indication | old MME/SGSN: ????????? 1. 標(biāo)記UE上下文在SGW,PGW,HSS中不可用(如果Serving GW change indication指示的話) | MME在發(fā)送 Context Acknowledge后創(chuàng)建會(huì)話之前會(huì)創(chuàng)建MM上下文,如果: 1.在Context Response或其他根本沒有承載上下文,則拒絕TAU; 2.有,則1.創(chuàng)建MM上下文;2.釋放UE中未激活的EPS承載網(wǎng)絡(luò)資源(EPS bearer status的作用) | |||
| 8 | ?Create Session Request | 請(qǐng)求會(huì)話建立 | IMSI, bearer contexts, MME Address and TEID, Type, ?the Protocol Type over S5/S8, ?RAT type | bearer contexts, MME Address and TEID, Type, ?the Protocol Type over S5/S8, ?RAT type | new SGW: 1.更新上下文 2.分配資源:TEID-U/-C等 | 1.要帶MME 的TEID-C/Address-C 2.PGW的控制地址放在 the Protocol Type over S5/S8中,用戶面地址放在bearer contexts中 | ||
| 9 | ?Modify Bearer Request | 通知PGW RAT Type的變化(計(jì)費(fèi)) | Serving GW Address and TEID, RAT type | Serving GW Address and TEID, RAT type | PGW: 1.更新上下文 2.分配資源:TEID-U/-C等 | 1.要帶SGW的TEID-C/-U/Address-C-U | ||
| 9a | PCEF initiated IP?CAN ?Session Modification? | 通知PCRF RAT Type的變化(計(jì)費(fèi)) | RAT type | 使用動(dòng)態(tài)PCC | PCRF: 1.異步更新計(jì)費(fèi)等情況,PGW不會(huì)等待PCRF的處理。 | 如果PCRF響應(yīng)導(dǎo)致EPS承載的修改,PDN-GW應(yīng)發(fā)起承載更新流程 | ||
| 10 | ?Modify Bearer Response | MSISDN , Charging Id | PGW的TEID-C/-U/Address-C-U | new SGW: 1.更新上下文 | ||||
| 11 | ?Create Session Response | Serving GW address and TEID for user plane and control plane and PDN?GW TEIDs (for GTP-based S5/S8) or GRE keys (for PMIP-based S5/S8) for uplink traffic and control plane | SGW、PGW的TEID-C/-U/Address-C-U | new MME: 1.檢查有沒有UE的簽約上下文。沒有則向HSS請(qǐng)求 | 為啥除了SGW的TEID(s)還帶PGW的TEID(s)? 答:必須更新MME中的Bearer contexts(見Context Response中返回參數(shù))。 | |||
| 12 | Update Location Request? | 向HSS請(qǐng)求UE的簽約上下文 | MME Identity, IMSI, Update Type, MME Capabilities | MME Identity, IMSI, Update Type, MME Capabilities | HSS: ? 可以允許或不允許更新位置。 ? 允許:繼續(xù) ? 不允許:發(fā)TAU Reject | |||
| 13 | Cancel? Location? | 取消掉old MME/SGSN中的位置信息(MM上下文) | IMSI, Cancellation Type | old MME/SGSN: 1.刪除MM上下文; 2.如果有Iu連接,釋放Iu連接 | ||||
| 14 | Cancel Location Ack | IMSI | ||||||
| 15 | Iu Release Command | 如果有Iu連接,釋放Iu連接 | ||||||
| 16 | Iu Release Complete | |||||||
| 17 | Update Location Ack | IMSI, Subscription Data | IMSI, Subscription Data | new MME: ? 檢查TA是否允許UE的接入 ? 允許:接受TAU ? 不允許:發(fā)TAU Reject | ||||
| 18 | ?Delete Session Request? | 刪除到old S-GW的EPS承載資源 | Cause, TEID | 如果在Context Acknowledge消息中收到Serving GW change indication,表明SGW變化了 | 刪除到old S-GW的EPS承載資源 | 除了這步刪除到old S-GW的EPS承載資源, 在第4步中啟動(dòng)的定時(shí)器超時(shí)時(shí), old MME/S4 SGSN會(huì)釋放任何本地MME或SGSN承載資源, | ||
| 19 | Delete Session Response? | TEID | old SGW: ? 丟棄為這個(gè)UE緩存的任何分組 | |||||
| 20 | TAU Accept? | GUTI, TAI list, EPS bearer status, NAS sequence number, NAS-MAC, ?IMS Voice over PS session supported Indication | GUTI, TAI list, EPS bearer status | UE: ? 根據(jù)EPS bearer status刪除UE中多余激活的承載; new MME 和 UE: ? 若TAU request中設(shè)置了active flag,則建立S1連接和RRC連接。 | 建立S1連接和RRC連接的方法: ?? 同附著流程中17-22步一樣. Initial context setup Request消息可和TAU Accept結(jié)合,減少消息的條數(shù)。回來的Initial context setup Response不能與TAU Complete結(jié)合,一是因?yàn)閑NodeB不可能等到UE響應(yīng),二是TAU Complete可能消息還不會(huì)發(fā)送. | |||
| 21 | TAU Complete | 確認(rèn)收到了 新分配的GUTI | ? | 當(dāng)新分配了GUTI時(shí)發(fā)送 | ||||
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