Debug Cisco Voice Gateway

 Debugging Cisco Voice 

Debug Ref Doc

I recently came across the following command  “call filter match-list” command,  it’s been available on Cisco IOS Voice Gateways since release 12.3(4)T. and I have to say I found it very very useful so here's how to use it.

If you ever done a debug output from a busy voice gateway, you  would know that it spits out ton's of information constantly but you can use this command to trim down the information to just to the phone calls you are looking for.  

Before you begin to use it create the call filter match-list in global configuration mode. The syntax to get started looks like this:  

CUBE(config)#call filter match-list 1 voice  

Now, you can define one or several criteria to match, including, but not limited to, incoming calling number, outgoing calling number, incoming port, outgoing port and dial peer.  

The filter below would match on outgoing calling number and outgoing voice port

CUBE(config)#call filter match-list 1 voice outgoing calling-number 888XXX outgoing port 0/1/0  

Next enable the filter with the “debug condition match-list 1 {exact-match | partial-match}” command.

I normally start with exact match, and then switch over to partial match if I don’t see the debug output I'm looking for.  

Once the filter is enabled, you can then turn on the debug you want from the debugs that work with the call filter list. This feature supports many of the more common debugs you would use, including debug isdn q931, debug voip ccapi inout, debug ccsip messages, debug vtsp.

Once enabled, all of these normally chatty debugs will be filtered down to the criteria you set up in the call filter list. For example, if the filter above were used as exact match, then only calls with the outgoing calling number 888XXX and matching the outgoing defined voice port would be part of the debug output.  

If you have configured your call filter list and are wondering if you applied it correctly, you can always do a show debug and you should see something like this:  

CUBE#show debug The following ISDN debugs are enabled on all DSLs: debug isdn error is ON. debug isdn q931 is ON. (filter is ON)  

Notice the (filter is ON). Also, if you had partial match as the criteria for your debug call filter list, you would see “debug condition match-list is set to PARTIAL_MATCH” when you entered this command.  

To turn off the filter, just enter the CUBE(config)#no debug condition match-list 1

CUBE(config)#call filter match-list 1 voice 

CUBE(conf-call-filter-mlist)#incoming calling-number 0773XXXXXX

CUBE#debug condition match-list 1 partial-match 

CUBE#debug ccsip calls 

CUBE#ter mon

Once done this you should only see calls from the mobile number above