ISDN dial-peers hunt

[Youssef Aoufi]

Hi there,

I have some questions regarding my PSTN calls.

We have a CUCM and 2x AS5400 gateway with 4 PRIs configured  in a route list.

When a user calls a switched off cell phone , it takes forever to receive a busy tone.

Looking at the debugs , we are receiving an isdn disconnect cause 20 : subscriber absent . But the gateway stills route the call to the next dial-peers going through different PRIs. 

I was able to stop routing to the second gateway using the service parameter on CUCM :  Stop Routing on Q.931 Disconnect Cause Code but i am looking for a way to stop the routing through the dial-peers when the subscriber is absent.

On the other hand, we are receiving a busy tone and not the service provider announecement.

When i call the same number using my cell phone i receive a message from the telco (the user is not available.....) but using the ip phone we receive a busy tone.

Thanks in advance

[Ayodeji Okanlawon]

What is the protocol you are using to talk to CUCM? SIP or H323. If you are using SIP you can map the cause code as follows..

sip-ua

set pstn-cause 20 sip-status 486

If you are using H323

conf t

application

map

q850-cause 20 q850-cause 17

Then configure the gateway as follows

conf t

no voice hunt user-busy

So basically you are telling the gateway not to hunt to next dial-peer when we get 486..

For the other issue, again we need to know what protocol you are using to talk to CUCM. If its SIP then you should enable PRACK on CUCM.

[Youssef Aoufi]

Hi Ayodeji, 

It's a real pleasure to get an answer from such a sip expert. 

I read many of your documents and cases, your sip knowledge is really impressive :) 

In my case, i am using sip as well so i will test your suggestion and get back to you asap. 

Thanks man :) 

Best regrads

[Wilson Samuel]

Hi,

Wow such a great thread. I learned a lot from your discussion. Rated +5 to both you.

Plz rate all helpful posts :-)

[Daniele Giordano]

Hi. To stop the hunting process on the gateway at dial-peer level you can simply add the command "huntstop" in the dial-peer config.

Please, check also if in your AS5400 config there are these commands:

voice call send-alert
voice call convert-discpi-to-prog
voice rtp send-recv

Regards.

[Ayodeji Okanlawon]

Daniele,

I am sure you can do that but you should not be doing it. What happens when one of your CUCM server is down and CUCM sends a 503 service unavailable to your gateway? How does your gateway hunt to the next dial-peer to try the second CUCM.

The voice call convert-discpi-to-prog command turns an ISDN disconnect message into a progress message

voice call send-alert

To enable the terminating gateway to send an alert message instead of a progress message after it receives a call setup message, use the voice call send-alert command in global configuration mode. To reset to the default, use the no form of this command.

None of these commands have anything to do with the issue reported here? Perhaps I am missing something..