FXO ports on LGW in Webex Calling

[danielsanmartin]

Hello Community, good morning.
I am looking for information on how to configure FXO ports on a local Webex Calling gateway.
The idea is that incoming calls through the FXO ports are directed to the auto attendant.
Next, I would like users to be able to use the analog telephone lines connected to the FXO ports for external calls using a prefix, in case of SIP frame failure.
I hope you can guide me to carry out this configuration. I was searching everywhere and couldn't find anyone consulting on this topic.

Regards

[danielsanmartin]

I managed to solve the issue of incoming calls through the FXO ports.
Now, it remains to solve the issue of outgoing calls.
What you would need to do is for users to make outgoing calls through the SIP frame and their assigned number. But if they include a prefix before the desired number, calls should go out through the FXO ports.
If anyone can give me any ideas on how to do this, it would be a great help.

[Roger Kallberg]

Something along with this could work.

voice class dpg 200
 description incoming WxC to LGW FXO
 dial-peer 210
!
voice class uri FXO sip
 pattern <prefix> !possibly you'd need more to match just that pattern
!
dial-peer voice 200 voip
 description Incoming Dial-Peer from Webex Calling for calls to FXO
 max-conn 250
 session protocol sipv2
 destination dpg 200
 incoming uri request FXO
 voice-class codec 99
 voice-class stun-usage 200
 voice-class sip profiles 100 inbound
 voice-class sip tenant 200
 dtmf-relay rtp-nte
 srtp
 no vad
!
dial-peer voice 210 pots
 description Outbound Dial-Peer for calls to FXO
 !rest of the dial-peer config for sending calls to FXO port

It's not a ready made configuration example, you'd need to modify it to fit you needs.

[danielsanmartin]

Thanks Roger. With the command voice class uri FXO sip pattern <prefix> would the prefix that users would use to use the lines connected to the FXO ports be detected?

A Cisco support technician suggested creating a new trunk in Webex Calling to route calls through the FXO ports. How do you see this idea? Makes sense? Is this implementation possible?

Thanks again

Regards 

[Roger Kallberg]

Yes that’s what I meant. You’d need to use a string to match the inbound call that is specific enough to only match those calls.

Should be doable, but seems unnecessary complex to have another trunk just for that call scenario.

Have a look at this document for ideas on how you could match the call. Explain Cisco IOS and IOS XE Call Routing 

[danielsanmartin]

Hi Roger,

I wouldn't be thinking about how to implement the issue of using a prefix so that outgoing calls bleed through the FXO ports.
Debugging ccsip messages to calls with and without prefix, the format is identical and I can't find any difference to be able to identify the pattern that I should place in the voice class uri FXO sip command of the example you gave me

Regards

[Roger Kallberg]

There must be a difference, Webex MT should not do any modification of this before sending it to the LGW. Can you please share the outputs received by your LGW in two different text files that you attach to the post? Feel free to mask out any sensitive data by changing the output, just make sure to not alter it so that any information is lost.

[Roger Kallberg]

It just came to mind, how are you routing the call to your LGW from Wbx MT? Are you using Dial Plan configuration or are you letting the call hit the native number plan that exists in MT.

[danielsanmartin]

No special dialing plan is being used. Only the one that is already included in Webex Calling.

I am not able to upload the TXT files with the results of the debug ccsip messages command. The following error appears:

Correct the highlighted errors and try again.

The attachment's with_prefix.txt content type (text/plain) does not match the file extension and has been removed.
The content type without_prefix.txt of the attachment (text/plain) does not match the file extension and has been removed.

Could you tell me how to solve it?

[Roger Kallberg]

No idea on the error uploading text files. I’ve never had issues with this, but I’ve heard of a few others that also had similar issue.

In Wbx MT create a Dial Plan configuration that routes the prefixed calls to your LGW so that you don’t rely on the native call routing as you have zero insight into how that operates.

[danielsanmartin]

Hello Roger,
I have configured the dialing plan with +99!.
In the debug I see that the calls are directed to sip:+99XXXXXXXX@192.168.0.247:5061.
I configured what you suggested above, adapting it to my LGW configuration:

voice class uri FXO sip
pattern sip:+99

voice class dpg 500
description incoming WxC to LGW FXO
dial-peer 5001

dial-peer voice 500 voip
description Incoming Dial-Peer from Webex Calling for calls to FXO
max-conn 250
session protocol sipv2
destination dpg 500
incoming uri request FXO
voice-class codec 200
voice-class stun-usage 100
voice-class sip profiles 200 inbound
voice-class sip tenant 200
dtmf-relay rtp-nte
srtp
don't go

dial-peer voice 5001 pots
trunkgroup FXO
description Outbound to PSTN/FXO
translation-profile outgoing OutgoingPSTN
destination-pattern BAD.BAD
extra forward-digits

I am not seeing calls using dial-peer 500. They are always going from dial-peer 100 to dial-peer 200 like normal calls that do not use the prefix.

What could be happening?

[Roger Kallberg]

If you share the SIP dialogue of the call it would be easier to help you. Also please share the output from debug voip ccapi inout together with the output from debug ccsip message and debug ccsip non-call.

[danielsanmartin]

I attach the requested debugs

[Roger Kallberg]

The call is not making a match on the string you have defined. Try using this.

voice class uri FXO sip
 pattern +99(.*)

[danielsanmartin]

When I apply the suggested pattern I get this error:
pattern +99(.*)
% ?+* follows nothingpattern pattern should be of format ^([][0-9A-Za-z_\|@;:=%!~\/()*+^$&?#--.])*$