TVOICE – Fundamentals of Troubleshooting UC

TVOICE – Fundamentals of Troubleshooting UC

  • Updated Physical and Logical topologies
  • List of IP Ranges and Subnets
  • List of protocols used on the network
  • List of ACLs and FWs and their logical locations
  • Baseline of normal network traffic to distinguish from abnormal behaviour needing troubleshooting

4 Main Troubleshooting Areas

  • Call Processing Systems: CUCM, CME, CUBE
  • Unified Applications: Unity Connection, CUPS, UCCX
  • UC Endpoints: IP Phones, CIPC, CUPC
  • Network Infrastructure

Troubleshooting Methodology

  • Systematic Approach
  • Document each problem as it arises

Problem Solving Model

  • Define Problem
  • Gather Facts
  • Consider Possibilities
  • Create Action Plan
  • Implement Action Plan
  • Analyse Results – Do Problems Symptoms Stop? YES Problem Resolved/Document Facts NO Re-Use the Process – Gather Facts

Available Troubleshooting Tools


-Unified Serviceability

  • Alarms
  • Traces
  • CAR
  • Control Center Services
  • Dialed Number Analyzer


  • Alerts
  • Traces
  • Syslog Viewer
  • Performance Monitoring


-Gateway Tools

  • show commands
  • debug commands

-Other Tools



  • System Diagnostic Interface
  • Contain run-time events that occur in specific software routines
  • typically used by the administrator


  • Signaling Distribution Layer
  • Contain call-processing information from CCM and CTI services
  • Typically used by CIsco TAC


  • Java application traces
  • Typically used by Cisco TAC

Two Ways to Enable Trace Collection

Activate Troubleshooting Traces:

  • Per Server/Service
  • Cisco Unified Serviceability -> Trace -> Troubleshooting Trace Settings
  • Turns on ALL possible trace options for given server/service

Configure Trace Settings:

  • Per Server/Service
  • Unified Serviceability -> Trace -> Configuration
  • Allows use of filters to be used to customise selective subsets of services
  • Less info to be processes, less impact on performance
  • Likely to miss key, relevant information

CUCM to SCCP IP Phone Communication

CCM|StationInit (Message from IP Phone to CUCM)

  • SoftKeyEvent
  • KeypadButton
  • Stimulus (each button on phone is pressed)

CCM|StationD (Message from CUCM to IP Phone)

  • Phone Display (SetLamp, CallState, SelectSoftKeys)
  • Progress Tones (SetRinger, StartTone, StopTone)
  • Call Information (DialedNumber, CallInfo (includes callingParty, alternateCallingParty), DisplayNotify (Not enough bandwidth)
  • RTP Flows (StartMediaTransmission,StopMediaTransmission,OpenReceiveChannel, CloseReceiveChannel)
  • CCM|DigitAnalysis (during analysis) – pss, or ToDFilteredPss, cn, fqcn, dd, dac
  • CCM| (after matching a route pattern) – PretransformCallingParty, CallingPartyNumber,FullyQualifiedCalledPartyNumber, DialingPattern, PretransformDigitString
  • CCM|RouteList – RouteListName, RouteGroup, RouteListCdrc (skipToNextMember says next route group being examined or executeRouteAction says current device being attempted)
  • CCM|SMDMSharedData shows device name after findLocalDevice – shows device or route list references from pattern and while processing route list.
  • CCM|Locations – reserveBandwidth shows required BW (bw), current BW (curr) and max BW (max)
  • CCM|RegionsServer – matchCapabilities shows max permitted BW consumed by codec
  • CCM|MediaResourceManager – sendMTPXcoderAllocationRequest indicates that an MTP or Transcoder is required – capCountRegion shows region for both endpoints – mrgl shows MRGL to be used to find media resources to be allocated
  • CCM|MediaTerminationPointControl – getResourceAllocated Device Name indicates successful allocation of transcoder or MTP and shows device by name