簡介
本文檔介紹如何排除4G配售成功率(ASR)主要績效指標(KPI)降低故障。
可能的情況
4G ASR效能下降可能是由多種因素造成的:
- 網路問題
- 呼叫流特定問題
- 特定於節點的問題
- 配置問題
- RAN結束問題
初始分析所需的日誌
- 突出顯示降級的KPI趨勢圖。
- 用於度量的KPI公式。
- 自問題開始以來,原始批次統計資料計數器和原因代碼趨勢。
- 在問題時段內,以30分鐘間隔捕獲兩個顯示支援詳細資訊(SSD)例項。
- 從降級前兩小時到當前時間收集的系統日誌。
- 捕獲以下日誌:
Mon-sub/pro traces
Logging monitor msid
故障排除順序
1.確定ASR公式:
1-((emm-msgtx-decode-failure+emm-msgtx-attach-rej-gw-reject+emm-msgtx-attach-rej-activation-reject+emm-msgtx-attach-rej-svc-temp-out-of-order+emm-msgtx-attach-rej-protocol-error+emm-msgtx-attach-auth-failed+attach-proc-fail-max-retx-auth-req+attach-proc-fail-max-retx-sec-mode-cmd+attach-proc-fail-max-retx-attach-accept+attach-proc-fail-setup-timeout-exp+attach-proc-fail-sctp-fail+attach-proc-fail-guard-timeout-exp+attach-proc-fail-max-retx-esm-info-req+emm-msgtx-attach-rej-gw-auth-failed+emm-msgtx-attach-rej-insuff-resources+emm-msgtx-attach-reject-congestion+emm-msgtx-attach-reject-severe-network-failure+emm-msgtx-network-failure ) / (epsattach-imsi-attempted+epsattach-guti-local-attempted+epsattach-guti-foreign-attempted+epsattach-ptmsi-attempted+combinedattach-imsi-attempted+combinedattach-guti-local-attached+combinedattach-guti-foreign-attempted+combinedattach-ptmsi-attempted))
2.根據公式,有多個計數器用於計算ASR,因此從批次統計資料中,您需要檢查每個計數器的KPI趨勢。
3.將關鍵業績指標趨勢與無問題的時間表和有問題的時間表進行比較。
4.從KPI公式中確定有問題的批次統計資料計數器後,您需要檢查此計數器如何根據流程進行定義,並嘗試建立模式。
5.此外,使用時間間隔為3至5分鐘的多次迭代從節點收集斷開原因。
您可以找到在不同時間戳收集的兩個SSD的斷開原因差異。從delta斷開快速增加的斷開原因可以歸因於KPI降級的原因。此外,有關所有斷開連線的說明,請參閱思科的《統計資料和計數器參考》;https://www.cisco.com/c/en/us/td/docs/wireless/asr_5000/21-23/Stat-Count-Reference/21-23-show-command-output/m_showsession.html。
show session disconnect-reasons verbose
以下是解決因斷開原因「MME-HSS-User-Unknown」增加所導致效能下降情況的故障排除步驟示例。請參閱https://www.cisco.com/c/en/us/support/docs/wireless/mme-mobility-management-entity/214633-troubleshoot-4g-asr-kpi-degradation-due.html。
6.根據節點型別檢查egtp統計資訊。
--- SGW end -----
show egtpc statistics interface sgw-ingress path-failure-reasons
show egtpc statistics interface sgw-ingress summary
show egtpc statistics interface sgw-ingress verbose
show egtpc statistics interface sgw-ingress sessmgr-only
show egtpc statistics interface sgw-egress path-failure-reasons
show egtpc statistics interface sgw-egress summary
show egtpc statistics interface sgw-egress verbose
show egtpc statistics interface sgw-egress sessmgr-only
---- PGW end -----
show egtpc statistics interface pgw-ingress path-failure-reasons
show egtpc statistics interface sgw-ingress summary
show egtpc statistics interface sgw-ingress verbose
show egtpc statistics interface sgw-ingress sessmgr-only
--- MME end -----
show egtpc statistics interface mme path-failure-reasons
show egtpc statistics interface mme summary
show egtpc statistics interface mme verbose
show egtpc statistics interface mme sessmgr-only
7.要進一步分析並排除KPI降級故障,請捕獲mon-sub/mon pro呼叫跟蹤並考慮使用外部工具獲取Wireshark跟蹤。這些跟蹤有助於確定導致問題的特定呼叫流。
用於捕獲Mon子跟蹤的命令如下:
monitor subscriber imsi
---------- verosity level +++++,A, S, X, Y, 19. 26, 33, 34, 35
More options can be enabled depending on the protocol or call flow we need to capture specifically
8.如果由於KPI降級百分比極小而無法捕獲跟蹤(如mon-sub),則捕獲系統級別的調試日誌。此外,捕獲sessmgr和egptc的調試日誌,如果可疑問題涉及HSS/RAN等實體,則根據特定問題捕獲s1-ap/diameter的調試日誌。
logging filter active facility sessmgr level debug
logging filter active facility egtpc level debug
logging filter active facility diameter level debug ----- depending on scenario
logging filter active facility s1-ap evel debug ----- depending on scenario
logging active ----------------- to enable
no logging active ------------- to disable
Note :: Debugging logs can increase CPU utilization so need to keep a watch while executing debugging logs
9.一旦從debuglogs中獲得任何線索,您就可以捕獲該特定事件的核心檔案,並在其中看到錯誤日誌:
logging enable-debug facility sessmgr instance
eventid 11176 line-number 3219 collect-cores 1
For example :: consider we are getting below error log in debug logs which we suspect can be a cause of issue
and we don;t have any call trace
[egtpc 141027 info] [15/0/6045
_handler_func.c:10068] [context: MME01, contextID: 6] [software internal user syslog] [mme-egress] Sending reject response for the message EGTP_MSG_UPDATE_BEARER_REQUEST with cause EGTP_CAUSE_NO_RESOURCES_AVAILABLE to
So in this error event
facility :: sessmgr
event ID = 141027
line number = 10068
以下是解決此問題的各個步驟。