how to debug an incoming isdn call

[carl_townshend]

Hi there

Im having some issues with my phone system, its a CUCM and a 3845 h323 gateway

Incoming calls with an unknown number are getting dropped. The provider says its the phone system.

Is there a way I can debug the phone system to actually see my call coming in?

what commands should I run ?

is there anything on the phone system I can look for to see why it would drop calls from an unknown number?

cheers

Carl

[Gordon Ross · Accepted solution]

To see the ISDN side of things, telnet/SSH onto the H323 gateway. Enter enable mode, then type:

# term mon

# debug isdn q931

This shows you all ISDN calls going through the gateway.

If it's a busy gateway, there are a couple of ways you can reduce the amount of information you receive.

If you have multiple ISDNs, and you can be certain which interface the call will only come in on, you can do:

# debug isdn q931 int ser0/1/0:15

(Replace ser0/1/0:15 with the name of the ISDN interface the call will come in on)

If you know either the number the caller is calling from, or what number they are dialing, you can do:

# debug cond calling XXXXX

or

# debug cond called XXXXX

You can have multiple "debug cond"s configured.

Once you've finished clean up and disable all debugs. Do:

# no debug all

If you used the "debug cond" command, do:

# no debug cond all

These commands will show you what your provider is sending you (and what you're sending back) If you want to know what CUCM is doing with the call when it receives it, well, that's another story....

GTG