SIP SRST - Extension to Extension calling not working

[Netplace Support]

Hi ,

I am facing problem during SIP SRST. We are using 2921 CME SRST router and SIP phones are getting registered on router in SRST mode.

But extn to extn calling is not working. I have attached show run of the router.

When i executed, below commands, i got error that "unable to access default file".

"application

  service alternate default "

Please guide me on this issue.

[Kirill Glushenkov · Accepted solution]

Hello!

For fallback from MGCP u need: 

application 

  global

    service alternate default

You alrady have it

Do u have any problems with SCCP endpoints? Calls from SCCP to SIP?

Please, post 'debug ccsip messages' while trying to call.

Regards,

Kirill

[Netplace Support]

Hi Kirill,

Thanks for your reply. As I mentioned earlier, I was getting error while configuring commands for MGCP fallback.

Actually I had executed commands in SRST mode when Gateway was not registered with CUCM ie MGCP was down, hence it was giving error for "Application.... global .. commands".

I reconfigured same configuration keeping gateway registered with cucm & reloaded the router. Post this, tested SRST n extension to extension calling starts working.

Thanks for your valuable time.

Rgds

Harshali Nirgun