【正文】 er N1header分層封裝－消息頭的概念Layer 4Layer 2Layer 1Introduction to protocolsLayer 3Layer 4Layer 2Layer 1Layer 3Peertopeer protocols端到端協(xié)議應用表達對話傳輸網(wǎng)絡數(shù)據(jù)鏈路物理NetworkData LinkPhysicalLayer 7Layer 6Layer 5Layer 4Layer 3Layer 2Layer 1Introduction to protocolsLayer 0應用表達對話傳輸網(wǎng)絡數(shù)據(jù)鏈路物理OSI 參考模型Introduction to protocols信息交互要解決的第一個問題：數(shù)據(jù)流如何傳遞？利用什么媒介，以什么方式？?比特流的傳輸Layer 1 物理層Introduction to protocols問題 2：一連串的數(shù)據(jù)流中，哪里是開始，哪里是結束？?從比特流中正確地識別出消息（報文），并盡量減少未識別出的差錯?幀定位?差錯控制?序列號和重發(fā)機制Layer 2 數(shù)據(jù)鏈路層Introduction to protocolsFlag Check sumLayer 3 dataSequence numberAddress Flag數(shù)據(jù)鏈路層Introduction to protocols問題 3：一條消息如何從一點到達另一點，并最終到達其目的地；多個用戶的消息同時存在時，如何區(qū)別？?實際路由（用戶路由信息）?用戶復用Layer 3 網(wǎng)絡層Introduction to protocolsL2消息頭 連接參考 Layer 4 數(shù)據(jù)Layer 3 數(shù)據(jù)Layer 3 網(wǎng)絡地址Introduction to protocols操作維護 信令消息Layer 2Higher layersLayer 2 尋址Introduction to protocols連接參考MS 1 MS 2Layer 3Higher layersLayer 3 尋址 L1層協(xié)議介紹216。Lapdm： K＝ 1， 即發(fā)送－等待。L2鏈路層 協(xié)議分析LAPD、 LAPDm、 MTP2LAPD包括下列功能/a) 在 D信道上提供一個或多個數(shù)據(jù)鏈路連接。P/F：當該消息為命令時，該比特為 P比特，表示詢問（ Polling)比特 ,置 “1”要求對方予以響應；當該消息為響應時，該比特為 F比特，表示最后（ Final)比特，置 “1”表示該響應是在對方要求下回的。SCCP連接釋放n RLSD： 釋放消息n 包括 SLR和 DLRn RLC： 釋放完成n 只有 DLRn 這個規(guī)程完成后，雙方釋放相應的資源，包括釋放 SLR和 DLR。切換分析216。ABIS口分析216?？赏ㄟ^進行撥打測試并進行信令跟蹤，或?qū)Ω鹘涌陔娐窌r隙占用時長占用、頻度進行統(tǒng)計分析得到定位；呼叫失敗。話音接通率分析，通過對 E口、 A口信令進行統(tǒng)計分析，對未接通的流程進行歸類統(tǒng)計并作。（如接續(xù)時長、話音接通率等）216。應用范圍 通過對系統(tǒng)消息、測量報告、指配命令、切換命令等消息具體內(nèi)容的分析，準確掌握問題發(fā)生時源小區(qū)的具體信道和無線狀況、目標小區(qū)的具體信道和無線狀況。 TUP協(xié)議介紹 ISUP協(xié)議介紹 GSM 信令流程呼叫接續(xù)流程；位置更新流程；切換流程MSCMS BSCChannel activation ackChannel activationEncryption mandChannel requiredComplete Layer 3 Info.Authentication requestCall proceedingCipher Mode CompleteSABM(cm_serv_req)Immediate assign mandestablish indicationBTSChannel requestUA(cm_serv_req)Cipher Mode CommandImmediate assignment Authentication responseSetupCipher Mode CommandCipher Mode Complete主叫流程之一 呼叫接續(xù)流程主叫流程之二 MS BSCBTSMSCAssignment RequestChannel activation ackAssignment mandestablish indicationAssignment Complete Assignment CompleteDeactivate SACCHRelease requestRelease confirmRF Channle releaseRF Channel release ackAlertingConnectConnect acknowledgeSABMUAChannel activationMS BSCBTS MSC主叫流程之三Channel ReleaseRelease CompleteReleaseClear CommandRF Channle releaseDISCDeactivate SACCHRF Channel release ackRelease IndicationUADisconnectClear Complete被叫流程之一MS BSCBTS MSCChannel activation ackChannel activationEncryption mandChannel requiredComplete Layer 3 Info.Authentication requestCall confirmCipher Mode CompleteSABM(pag_resp)Immediate assign mandestablish indicationChannel requestUA(pag_resp)Cipher Mode CommandImmediate assignment Authentication responseSetupCipher Mode CommandCipher Mode CompletePaging CommandPaging Request Paging被叫流程之二MS BSCBTS MSCAssignment RequestChannel activation ackAssignment mandestablish indicationAssignment Complete Assignment CompleteDeactivate SACCHRelease requestRelease confirmRF Channle releaseRF Channel release ackAlertingConnectConnect acknowledgeSABMUAChannel activation被叫不在服務區(qū)MS BSCBTS MSCChannel activation ackChannel activationChannel requiredImmediate assign mandChannel requestImmediate assignment Paging CommandPaging Request PagingDeactivate SACCHRelease requestRelease confirmRF Channle releaseRF Channel release ackMS BSCChannel activation ackChannel act