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Sample Output from the show voice cause-code category-q850 Command: Example

Router# show voice cause-code category-q850

The Internal Error Category to Q850 cause code mapping table:-

 Error Configured Default    Description

Category  Q850     Q850

   128     27        3  Destination address resolution failure

   129     38      102  Call setup timeout

   178     41       41  Internal Communication Error

   179     41       41  External communication Error

   180     47       47  Software Error

   181     47       47  Software Resources Unavailable

   182     47       47  Hardware Resources Unavailable

   183     41       41  Capability Exchange Failure

   184     49       49  QoS Error

   185     41       41  RTP/RTCP receive timer expired or bearer layer failure

   186     38       38  Signaling socket failure

   187     38       38  Gateway or signaling interface taken out of service

   228     50       50  User is denied access to this service

   278     65       65  Media Negotiation Failure due to non-existing Codec

Troubleshooting VoIP Networks Using Cisco VoIP Internal Error Codes

IECs are generated for errors that cause the gateway to release or refuse a call. This section provides procedural and reference information used to troubleshoot gateway-detected errors and resolve problems on the gateway and with other VoIP network entities.

Because fields within the IEC identify which network entity and subsystem originated an error, they can be used to diagnose and isolate failures that can cause call disconnects.

This section discusses troubleshooting scenarios using IECs to diagnose and resolve the problems described in the following sections:

•

Troubleshooting Two-Stage Dialing Failures

•

Troubleshooting Socket Failures

Troubleshooting Two-Stage Dialing Failures

The following example shows how to troubleshoot a two-stage dialing failure.

Symptom

The Cisco router or gateway rejects a call placed by a PSTN ISDN user after all the digits have been dialed.

Problem Description

The PSTN user enters a destination number that is routed through the PSTN ISDN switch, which sends an ISDN SETUP message to the router. The router tags the incoming call leg and sends back an ISDN CONNECT message. The caller receives second dial tone. The router then enters the digit collection stage to use the collected digits to route the call to the next hop, at which point the router rejects the call.

Troubleshooting Tasks

Perform the following steps to determine the reason for call failure.

Step 1

Use the voice iec syslog command to enable displaying of IECs as they are encountered in real-time.

Step 2

Use the voice iec statistics type iec command to configure the collection of IEC statistics.

Step 3

Use the show running-config command to verify IEC, ISDN, and dial-peer configuration, as shown in the following partial sample output:

Router> show running-config

Building configuration...

voice rtp send-recv

voice service voip

The following lines show the IEC configuration:

voice iec syslog

no voice hpi capture buffer

no voice hpi capture destination

voice statistics type iec

The following lines show the T1 configuration:

controller T1 0

 framing esf

 clock source line primary

 linecode b8zs

 cablelength short 133

 pri-group timeslots 1-24

The following lines show the ISDN configuration:

interface Serial0:23

 no ip address

 no logging event link-status

 isdn switch-type primary-ni

 isdn incoming-voice modem

 no cdp enable

The following lines show the dial-peer configuration. Because the dial-peer voice 1 is not configured for direct inward dialing (DID), the inbound call leg is considered to be configured for two-stage dialing, and the router returns a second dial tone.