长途来话接通率分析.doc

东方通信工程服务部GSM网长途来话接通率分析前言长途来话接通率是一个综合性指标，路由上涉及全网有线网络和本地无线网络，协议上包括MAP、TUP和BSSAP，局数据与多个MSC相关，需分析的统计数据来自TMSC、VMSC、OMCR和信令分析仪。本文不针对某种具体交换机，仅从网络原理和实际经验上分析。影响GSM网长途来话接通率常见的几种原因如下： MSRN（roaming number）路由出错 TMSC（汇接MSC）、VMSC（终端MSC）中继拥塞 T3212（手机周期性位置登记的时间间隔） 用户忙的比例 寻呼响应/寻呼次数的比例 被叫用户应答/振铃的比例 SDCCH、TCH拥塞高一 长途来话的呼叫流程分析1 一个成功的长途来话，信令流程如图1所示IAI(setup GMSC HLR TMSC VMSC/VLR BSC map_send_routing_informationmap_provide_roaming_numbermap_provice_roaming_number_ackmap_send_routing_information_ack IAI(MSRN)IAI paging paging ack ACM authentication request ACM authentication response cipher mode command cipher mode complete setup call confirmed assignment request assignment complete alertingANC connectANC connect ack GMSC HLR TMSC VMSC/VLR BSCCBK disconnectCBK release commandCLF release completeCLF clear commandRLG clear completeRLG图1 信令流程：一个成功的长途来话说明：【1】 GMSC指一次来话过程中的第一个MSC；TMSC指GSM网的长途汇接MSC；VMSC指被叫所在的MSC。【2】 大写字体 为TUP协议，小写字体 为MAP协议，小写字体 为BSSAP协议。【3】长途来话接通率考核点在TMSC。2 可见，长途来话的呼叫过程大致可分为三个部分（1） GMSC得到MSRN（MAP）【1】 GMSC根据被叫号码（DN），访问相应的HLR（H1H2H3）【2】 HLR访问被叫所在的VLR【3】 VLR返回MSRN（roaming number）给HLR【4】 HLR返回MSRN给GMSC（2） GSM长途网的话路接续（TUP）【1】 GMSC根据MSRN寻址，接续到TMSC【2】 TMSC根据MSRN寻址，接续到VMSC（3） VMSC部分【1】 VMSC把MSRN对应到IMSI（TMSI）【2】 发起寻呼【3】 被叫寻呼响应【4】 对被叫的鉴权、加密等过程【5】 为被叫指配陆地电路（MSCBSC间）、TCH【6】 被叫振铃【7】 被叫应答【8】 通话双方中的其中一方挂机，通话结束【9】 各网元的相关资源释放其中，【2】【9】和本地来话中的过程相同二 呼叫失败原因分析1 GMSC得到MSRN（1）可能的原因原因说明unknown subscriber空号absent subscriberT手机未登记，位置未知，或IMSI_detach；且呼叫转移（手机不可及）未激活call barred手机接入禁止forwarding violationno roaming number available没有MSRN可分配number changed手机已改号CUG rejectteleservice/bearer service not provisioned所申请业务不支持facility not supporteddate missing数据丢失unexpected data valuesystem failure系统错误（2） 可见，空号、无权漫游、无权被叫（停机）、被叫关机或未登记的情况不分配MSRN。因为长途来话接通率的考核点在TMSC，这样的呼叫不被统计在内。这也是减小T3212（手机周期性位置更新间隔），能提高长途来话接通率的原因。2 GSM长途网的话路接续可能失败原因说明原因分析及措施TMSC MSRN路由出错MSRN被送到不正确的VMSC，VMSC判断为空号或拨号不全检查TMSC路由数据和拨号方案TMSCVMSC中继拥塞呼叫因占不上中继而失败话务均衡或增加中继数量，检查中继选择方式TMSCVMSC信令链路不稳定或拥塞导致信令包丢失检查传输设备误码率或优化信令链路结构TMSC或VMSC内部处理出错内部拥塞检查交换机相关处理器的负荷TMSC或VMSC设备故障处理器、中继模块、信令模块等分析交换机告警信息，排除存在故障3 VMSC部分【1】可能失败原因说明原因分析及措施MSRN出错同2中的TMSC MSRN路由出错TMSC修改数据用户忙增加特服寻呼无应答提高无线覆盖率降低SDCCH拥塞鉴权、加密失败减少鉴权、加密次数降低SDCCH拥塞TCH指配失败降低TCH拥塞降低掉话率振铃超时、振铃早释、振铃后被叫用户拒绝接听【3】 根据经验，在无线网络良好的情况下，这部分对长途来话接通率的影响主要取决于三个比例：用户忙；寻呼响应比；振铃应答比。三 统计数据来源1 来自TMSC、VMSC的TGRP统计数据，和七号信令分析仪TUP层分析，可用来分析TMSC MSRN路由出错、TMSCVMSC中继拥塞的问题、及确定用户忙的比例。2 来自VMSC的统计数据，和七号信令分析仪BSSAP层分析，可用来分析寻呼响应比、鉴权/加密成功率、指配成功率。3 来自VMSC的统计数据和OMCR的统计，可用来分析应答/振铃比。4 来自OMCR的统计数据，可以分析SDCCH、TCH的拥塞情况。附录一 A接口及长途来路接通率分析一 A接口分析1 呼叫消息流程和消息参数 (来自2000/6/6 11:25-11:55 采集的A口信令) 结论：消息流程、参数正常。呼叫重建（call_reestablishment）和定向重试（directed_retry）因MSC不支持而被拒绝，BSS已关闭上述功能。 呼叫消息流程【1】Paging response Message sequence: 11:26:00.286 MSU nSCCP 2498h 2492h 1 UDT 2498h BSSAP 2492h BSSAP Paging IMSI 460007345649152 TMSI: B013E4FD CELLID LST 460 00 29460 11:26:01.479 MSU nSCCP 2492h 2498h 6 CR BSSAP Complete Layer 3 Information CELL ID 29460 7161 Paging response TMSI B013E4FD 11:26:01.569 MSU nSCCP 2498h 2492h 1 CC Cipher Mode Command 11:26:01.937 MSU nSCCP 2492h 2498h 6 DT1 Cipher Mode Complete 11:26:01.976 MSU nSCCP 2498h 2492h 1 DT1 TMSI reallocation command 460 00 7314 TMSI B022857B 11:26:01.991 MSU nSCCP 2498h 2492h 1 DT1 Setup CLG P NUMB 07349087807F 11:26:02.407 MSU nSCCP 2492h 2498h 6 DT1 TMSI reallocation complete 11:26:02.641 MSU nSCCP 2492h 2498h 6 DT1 Call confirmed 11:26:02.769 MSU nSCCP 2498h 2492h 1 DT1 Assignment Request 11:26:03.333 MSU nSCCP 2492h 2498h 6 DT1 Assignment Complete 11:26:03.435 MSU nSCCP 2492h 2498h 6 DT1 Alerting 11:26:08.656 MSU nSCCP 2492h 2498h 6 DT1 Connect 11:26:08.716 MSU nSCCP 2498h 2492h 1 DT1 Connect acknowledge 11:26:16.140 MSU nSCCP 2492h 2498h 6 DT1 Disconnect normal call clearing 11:26:16.222 MSU nSCCP 2498h 2492h 1 DT1 Release normal call clearing 11:26:16.439 MSU nSCCP 2492h 2498h 6 DT1 Release complete 11:26:16.486 MSU nSCCP 2498h 2492h 1 DT1 Clear Command Call control 11:26:16.537 MSU nSCCP 2492h 2498h 6 DT1 Clear Complete 11:26:16.569 MSU nSCCP 2498h 2492h 1 RLSD 11:26:16.579 MSU nSCCP 2492h 2498h 6 RLC 【2】Paging response smsMessage sequence: 11:26:16.913 MSU nSCCP 2498h 2492h 8 UDT 2498h BSSAP 2492h BSSAP Paging IMSI 460007349940756 TMSI: B0226258 CELLID LST 460 00 29460 11:26:19.355 MSU nSCCP 2492h 2498h 11 CR BSSAP Complete Layer 3 Information CELL ID 29460 7161 Paging response TMSI B0226258 11:26:19.460 MSU nSCCP 2498h 2492h 15 CC Authentication request 11:26:19.812 MSU nSCCP 2492h 2498h 11 DT1 Classmark Update 11:26:20.279 MSU nSCCP 2492h 2498h 11 DT1 Authentication response 11:26:20.356 MSU nSCCP 2498h 2492h 15 DT1 Cipher Mode Command 11:26:20.748 MSU nSCCP 2492h 2498h 11 DT1 Cipher Mode Complete 11:26:20.794 MSU nSCCP 2498h 2492h 15 DT1 CP-Data RP-Data Network to mobile station direction 8613800100500F 11:26:21.932 MSU nSCCP 2492h 2498h 11 DT1 CP-Acknowledge 11:26:22.166 MSU nSCCP 2492h 2498h 11 DT1 CP-Data RP-Acknowledge Mobile station to network direction 11:26:22.201 MSU nSCCP 2498h 2492h 15 DT1 CP-Acknowledge 11:26:22.218 MSU nSCCP 2498h 2492h 15 DT1 Clear Command Call control 11:26:22.274 MSU nSCCP 2492h 2498h 11 DT1 Clear Complete 11:26:22.310 MSU nSCCP 2498h 2492h 15 RLSD 11:26:22.320 MSU nSCCP 2492h 2498h 11 RLC 【3】CM service_request _oraginate callMessage sequence: 11:26:06.935 MSU nSCCP 2492h 2498h 15 CR BSSAP Complete Layer 3 Information CELL ID 29460 7162 CM service_request TMSI B0213CF3 11:26:07.017 MSU nSCCP 2498h 2492h 10 CC Cipher Mode Command 11:26:07.386 MSU nSCCP 2492h 2498h 15 DT1 Cipher Mode Complete 11:26:07.629 MSU nSCCP 2492h 2498h 15 DT1 Setup CLD P NUMB 1272812662 11:26:07.703 MSU nSCCP 2498h 2492h 10 DT1 Call proceeding 11:26:07.713 MSU nSCCP 2498h 2492h 10 DT1 Assignment Request 11:26:08.480 MSU nSCCP 2492h 2498h 15 DT1 Assignment Complete 11:26:14.337 MSU nSCCP 2498h 2492h 10 DT1 Alerting 11:26:14.955 MSU nSCCP 2498h 2492h 10 DT1 Connect 11:26:15.132 MSU nSCCP 2492h 2498h 15 DT1 Connect acknowledge 11:26:26.519 MSU nSCCP 2492h 2498h 15 DT1 Disconnect normal call clearing 11:26:26.593 MSU nSCCP 2498h 2492h 10 DT1 Release normal call clearing 11:26:26.933 MSU nSCCP 2492h 2498h 15 DT1 Release complete 11:26:26.975 MSU nSCCP 2498h 2492h 10 DT1 Clear Command Call control 11:26:27.025 MSU nSCCP 2492h 2498h 15 DT1 Clear Complete 11:26:27.058 MSU nSCCP 2498h 2492h 10 RLSD 11:26:27.067 MSU nSCCP 2492h 2498h 15 RLC 【4】cm_service_Emergency setup Message sequence: 11:26:40.884 MSU nSCCP 2492h 2498h 13 CR BSSAP Complete Layer 3 Information CELL ID 29460 7012 CM service_request TMSI B02208EE 11:26:40.976 MSU nSCCP 2498h 2492h 13 CC Cipher Mode Command 11:26:41.340 MSU nSCCP 2492h 2498h 13 DT1 Cipher Mode Complete 11:26:41.581 MSU nSCCP 2492h 2498h 13 DT1 Emergency setup 11:26:41.673 MSU nSCCP 2498h 2492h 13 DT1 Call proceeding 11:26:41.689 MSU nSCCP 2498h 2492h 13 DT1 Assignment Request 11:26:42.449 MSU nSCCP 2492h 2498h 13 DT1 Assignment Complete 11:26:42.533 MSU nSCCP 2498h 2492h 13 DT1 Alerting 11:26:42.537 MSU nSCCP 2498h 2492h 13 DT1 Connect 11:26:42.854 MSU nSCCP 2492h 2498h 13 DT1 Connect acknowledge 11:26:47.668 MSU nSCCP 2492h 2498h 13 DT1 Disconnect normal call clearing 11:26:47.713 MSU nSCCP 2498h 2492h 13 DT1 Release normal call clearing 11:26:47.948 MSU nSCCP 2492h 2498h 13 DT1 Release complete 11:26:48.024 MSU nSCCP 2498h 2492h 13 DT1 Clear Command Call control 11:26:48.090 MSU nSCCP 2492h 2498h 13 DT1 Clear Complete 11:26:48.132 MSU nSCCP 2498h 2492h 13 RLSD 11:26:48.142 MSU nSCCP 2492h 2498h 13 RLC 【5】cm_service_request smsMessage sequence: 11:27:14.968 MSU nSCCP 2492h 2498h 2 CR BSSAP Complete Layer 3 Information CELL ID 29460 7681 CM service_request TMSI B0228201 11:27:15.063 MSU nSCCP 2498h 2492h 10 CC Authentication request 11:27:15.202 MSU nSCCP 2492h 2498h 2 DT1 Classmark Update 11:27:16.134 MSU nSCCP 2492h 2498h 2 DT1 Authentication response 11:27:16.169 MSU nSCCP 2498h 2492h 10 DT1 Cipher Mode Command 11:27:16.599 MSU nSCCP 2492h 2498h 2 DT1 Cipher Mode Complete 11:27:17.569 MSU nSCCP 2492h 2498h 2 DT1 CP-Data RP-Data Mobile station to network direction 8613800731500F 11:27:17.616 MSU nSCCP 2498h 2492h 10 DT1 CP-Acknowledge 11:27:17.649 MSU nSCCP 2498h 2492h 10 DT1 CP-Data CP-Error Network to mobile station direction requested facility not subscribed 11:27:18.249 MSU nSCCP 2492h 2498h 2 DT1 CP-Acknowledge 11:27:18.290 MSU nSCCP 2498h 2492h 10 DT1 Clear Command Call control 11:27:18.365 MSU nSCCP 2492h 2498h 2 DT1 Clear Complete 11:27:18.404 MSU nSCCP 2498h 2492h 10 RLSD 11:27:18.413 MSU nSCCP 2492h 2498h 2 RLC 【6】CM service_request _ssMessage sequence: 11:26:27.596 MSU nSCCP 2492h 2498h 2 CR BSSAP Complete Layer 3 Information CELL ID 29460 7193 CM service_request TMSI B022886F 11:26:27.684 MSU nSCCP 2498h 2492h 11 CC Authentication request 11:26:28.292 MSU nSCCP 2492h 2498h 2 DT1 Authentication response 11:26:28.366 MSU nSCCP 2498h 2492h 11 DT1 Cipher Mode Command 11:26:28.760 MSU nSCCP 2492h 2498h 2 DT1 Cipher Mode Complete 11:26:29.005 MSU nSCCP 2492h 2498h 2 DT1 Register INVOKE INVOKE ID: 2 Interrogate SS 11:26:29.119 MSU nSCCP 2498h 2492h 11 DT1 Release complete RET RESULT INVOKE ID: 2 Interrogate SS 11:26:29.127 MSU nSCCP 2498h 2492h 11 DT1 Clear Command Call control 11:26:29.177 MSU nSCCP 2492h 2498h 2 DT1 Clear Complete 11:26:29.213 MSU nSCCP 2498h 2492h 11 RLSD 11:26:29.222 MSU nSCCP 2492h 2498h 2 RLC 【7】CM reestablishment Message sequence: 11:26:12.239 MSU nSCCP 2492h 2498h 10 CR BSSAP Complete Layer 3 Information CELL ID 29460 7392 CM reestablishment request TMSI B0217242 460 00 7314 11:26:12.259 MSU nSCCP 2498h 2492h 13 CREF 【8】Location updating Message sequence: 11:26:17.905 MSU nSCCP 2492h 2498h 10 CR BSSAP Complete Layer 3 Information CELL ID 29460 7661 Location updating request 460 00 7314 TMSI B0213A40 11:26:17.987 MSU nSCCP 2498h 2492h 6 CC Location updating accept 460 00 7314 TMSI B02288C4 11:26:18.132 MSU nSCCP 2492h 2498h 10 DT1 Classmark Update 11:26:18.594 MSU nSCCP 2492h 2498h 10 DT1 TMSI reallocation complete 11:26:18.640 MSU nSCCP 2498h 2492h 6 DT1 Clear Command Call control 11:26:18.690 MSU nSCCP 2492h 2498h 10 DT1 Clear Complete 11:26:18.723 MSU nSCCP 2498h 2492h 6 RLSD 11:26:18.732 MSU nSCCP 2492h 2498h 10 RLC 【9】IMSI_detach Message sequence: 11:26:18.717 MSU nSCCP 2492h 2498h 15 CR BSSAP Complete Layer 3 Information CELL ID 29460 7643 IMSI_detach indication TMSI B02282AA 11:26:18.812 MSU nSCCP 2498h 2492h 4 CREF 【10】inter-bsc handoverMessage sequence: 11:26:22.611 MSU nSCCP 2498h 2492h 14 CR BSSAP Handover Request CELL ID 29460 7141 CELL ID 29460 7162 11:26:22.752 MSU nSCCP 2492h 2498h 7 CC Handover Request Acknowledge Handover command HANDO REF: 01101111 11:26:23.095 MSU nSCCP 2492h 2498h 7 DT1 Handover Detect 11:26:23.394 MSU nSCCP 2492h 2498h 7 DT1 Handover Complete Normal release 11:26:26.608 MSU nSCCP 2492h 2498h 7 DT1 Handover Required Better cell CELLID LST 29460 7141 11:26:26.981 MSU nSCCP 2498h 2492h 14 DT1 Handover Command Handover command HANDO REF: 01001001 11:26:27.690 MSU nSCCP 2498h 2492h 14 DT1 Clear Command Handover successfull 11:26:27.742 MSU nSCCP 2492h 2498h 7 DT1 Clear Complete 11:26:27.783 MSU nSCCP 2498h 2492h 14 RLSD 11:26:27.792 MSU nSCCP 2492h 2498h 7 RLC 【11】intra-bsc handover11:26:40.592 MSU nSCCP 2492h 2498h 1 DT1 Handover Performed Better cell CELL ID 29460 7023 消息参数见表1。2 指配和切换的Cause 分析assignment、handover都是一个占用TCH的过程，可能失败的原因相同，所以没有把它们分开。下表中的数据来自2000/6/6 的数据，可以看出，没有异常的情况。causeforwardbackwardtotal比例radio interface message failure31130962032.01%radio interface failure28629257829.84%radio interface failure ,revision to old channel10362672937.64%equipment failure2130.15%no radio resource available550.26%ms not equipped110.05%protocal error between bsc and msc110.05%总和19373 呼叫相关比例(来自2000/6/6 的数据)Ciphering 98.5%Assignment98.5%Inter_bsc_handover_in92.3%Connect/alerting76.4%二 长途来话接通率分析1 流程及cause分析【1】 GMSC得到MSRN（GMSCHLRVLR MAP层） 可能失败原因unknown subscriberabsent subscriber(imsi_detach；imsi_ purge)This indicates that the location of the MS is not known (either the station is not registered and there is no location information available or the Provide Roaming Number procedure fails due to IMSI detached