VG224 Analogue phones on a VG224 do not work using SRST

[Peter Bishop]

Hi,

I have a IPT remote site connected via the WAN to a 2851 Router configured as the SRST gateway, so when the WAN link fails back to the main site where the main UCM Cluster resides, phones should be able to dial out via a local PSTN link.

When we carried out an SRST test by blocking the WAN traffic, all of the IP Phones worked fine and could dial out locally, but none of the analogue phones connected to the VG224 could dial out.

The VG224 is configured as an MGCP gateway, and the device pool the analogue phones are in has an SRST reference.

I have been searching CCO and it shows that the VG224 gateway is supported for SRST, but I am not sure whether it will work configured as an MGCP gateway, or whether I need to reconfigure it as an SCCP gateway.

Can anyone confirm or deny this?

If it should work configured as MGCP, does anyone have a sample config showing the MGCP commands for using SRST.

Many Thanks,

Peter

[njachiet]

Hi Peter,

You may have seen it, but could you review this doc?

http://www.cisco.com/en/US/tech/tk1077/technologies_tech_note09186a0080144630.shtml

What are the outputs of the following commands?

show ccm-manager fallback-mgcp

show call-manager-fallback all

show call-manager-fallback dial-peer

Thanks,

Nick

[Peter Bishop]

Hi Nick,

I've looked through the document and the sample network shows analogue ports actually connected to the SRST gateway, whereas my configuration differs in that the SRST gateway has the WAN and PSTN links on it and the analogues are on a separate VG224 gateway.

I have attached the 'cut down' configs of both gateway along with the 'show commands' at the end of each file; (where appropriate) if this helps.

Thanks,

Peter

Message was edited by: peterbishop. Files didn't upload

[njachiet]

Thanks Peter,

Could you add:

ccm-manager fallback-mgcp

And try again?

You may also need to add destination patterns to dial-peers, since the gateway will need to know where to route calls.

http://www.cisco.com/en/US/tech/tk1077/technologies_configuration_example09186a008012ecc6.shtml

Regards,

Nico

[Peter Bishop]

SRSTGW#show ccm-manager fallback-mgcp
Current active Call Manager:    10.203.105.50
MGCP Fallback mode:             Enabled/OFF
Last MGCP Fallback start time:  None
Last MGCP Fallback end time:    None

VG224GW#show ccm-manager fallback-mgcp
Current active Call Manager:    10.203.105.50
MGCP Fallback mode:             Not Selected
Last MGCP Fallback start time:  None
Last MGCP Fallback end time:    None

Best regards,

Peter

[Udit Mehrotra · Accepted solution]

With MGCP, you will need the following commands:

!

ccm-manager fallback-mgcp

!

application

global

  service alternate default

!

Additionally you will need dial-peers so that the default Call Control Application for IOS can be used to dial to the PSTN. You will need dial-peers pointing to FXS ports so that the ports may receive incoming calls.

Additionally you can choose to register them as SCCP to the SRST router but they will have to configured as Skinny endpoints on CM.

HTH

Udit

[Peter Bishop]

Thanks for your suggestions guys.

I will be making some changes next week, so will update this discussion with my results.

Thanks,

Peter

[Paul Hodgson]

Hi Peter

I know this thread is over two years old now, but did you get this working with the set up you described?

"SRST gateway has the WAN and PSTN links on it and the analogues are on a separate VG224 gateway"

Thanks

Paul

[shyam2014]

If the protocol of VG224 is SCCP will I need to add call-manager-fallback instead?

[Peter Bishop]

Hi, update to this issue - (albeit 2 years late)

SRST did work upon testing.

It was the command :- ccm-manager fallback-mgcp - that was missing and fixed the issue.

Without it, the command:-

VG224GW#show ccm-manager fallback-mgcp

Shows MGCP Fallback mode: as 'Not Selected'

Current active Call Manager:    10.203.105.50

MGCP Fallback mode:             Not Selected

Last MGCP Fallback start time:  None

Last MGCP Fallback end time:    None

Now on the gateway, the same command shows the following:-

Current active Call Manager:    10.203.105.50

MGCP Fallback mode:             Enabled/OFF

Last MGCP Fallback start time:  20:42:39 SUMMER Mar 24 2013

Last MGCP Fallback end time:    20:43:27 SUMMER Mar 24 2013

Otherwise - the config was as attached on 17th October 2007

Hope this helps