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Coherent way to trace calls through ISDN q931 debugs?

Call Center management wants me to determine if there is anything strange about calls that are processed by an agent that always are less than a minute. We have UCM, CVP, UCCX and 3925's.

I have elected to send syslog messages to server and try to parse these debugs (debug isdn q931)

Since the call center is rather busy, its tough to follow the "train" of the debug. Please reply with ways to do that, or logic to parse by.

Ultimeately I am trying to see if we disconnected the call, or if the inbound caller did....


Cisco Employee

Coherent way to trace calls through ISDN q931 debugs?

Hi Mark,

Here is a snippet from a test call I made:

JESSE: Search through the debug for the call you are interested in. I usually search for a calling or called number to get started. Once you find it scroll up a few lines and you should see the inbound setup message. Remember the terms inbound and outbound are from the perspective of the router. “Inbound <---” from the circuit or “Outbound --->” to the circuit.

072179: Nov  8 17:01:38.445 EST: ISDN Se0/1/0:23 Q931: RX <- SETUP pd = 8  callref = 0x01DF

        Bearer Capability i = 0x8090A2

                Standard = CCITT

                Transfer Capability = Speech 

                Transfer Mode = Circuit

                Transfer Rate = 64 kbit/s

        Channel ID i = 0xA18381

                Preferred, Channel 1

        Calling Party Number i = 0x2183, '5126582024'

                Plan:ISDN, Type:National

        Called Party Number i = 0x80, '0555'

                Plan:Unknown, Type:Unknown

JESSE: Make note of the callref id, this is how we will track our call. In this case the INBOUND callref id is 0x01DF. The outbound callref id will be the same except 0x0 will be replaced with 0x8

JESSE: Here you can see we send a call proceeding message back out to the circuit. (ringing)

072181: Nov  8 17:01:38.449 EST: ISDN Se0/1/0:23 Q931: TX -> CALL_PROC pd = 8  callref = 0x81DF

        Channel ID i = 0xA98381

                Exclusive, Channel 1

JESSE: When the call pickups on our end we send a message letting the circuit know we have connected and they respond with an acknowledgement.

072182: Nov  8 17:01:38.917 EST: ISDN Se0/1/0:23 Q931: TX -> CONNECT pd = 8  callref = 0x81DF

072183: Nov  8 17:01:38.953 EST: ISDN Se0/1/0:23 Q931: RX <- CONNECT_ACK pd = 8  callref = 0x01DF

072184: Nov  8 17:01:38.957 EST: %ISDN-6-CONNECT: Interface Serial0/1/0:0 is now connected to 5126582024 N/A

JESSE:In this case I hung up on my end first so you see the circuit telling us with an inbound message to tear down the call. If the user on our end hung up first you would see the opposite with us sending an outbound message.

072189: Nov  8 17:01:50.445 EST: ISDN Se0/1/0:23 Q931: RX <- DISCONNECT pd = 8  callref = 0x01DF

        Cause i = 0x8090 - Normal call clearing

072190: Nov  8 17:01:50.445 EST: %ISDN-6-DISCONNECT: Interface Serial0/1/0:0  disconnected from 5126582024 , call lasted 11 seconds

072191: Nov  8 17:01:50.445 EST: ISDN Se0/1/0:23 Q931: TX -> RELEASE pd = 8  callref = 0x81DF

072192: Nov  8 17:01:50.469 EST: ISDN Se0/1/0:23 Q931: RX <- RELEASE_COMP pd = 8  callref = 0x01DF

Hope this helps,


Cisco Employee

Coherent way to trace calls through ISDN q931 debugs?

Hi Mark,

It was well explained by Jesse, Addition to that, since you are trying to find the calls which are less than a minute.

Use the below link for Q931 disconnect Cause Codes and their description

It will help you check call disconnection side from the Cause i value you get from the debugs



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