Calling Party Number Modifications

[Brian Carscadden]

I have a need to translate calling party numbers from our fax server on outgoing PSTN calls.

The specific call path is: Fax Server -> SIP Trunk -> CUCM -> MGCP T1/PRI -> PSTN

Calls from our fax server will have non-routable/fake 10-digit calling party numbers. I need those numbers (approximately 50) to be translated after they leave the fax server so that they appear as different/real 10-digit calling party numbers to the PSTN.

Calling party number modifications via Route Pattern/List are not feasible, and my attempts to use Calling Party Transformation Patterns (Call Routing>Transformation>Transformation Patterns) don't appear to work for me, but perhaps I'm missing something. My TAC engineer doesn't seem to know ... they're investigating ... so I'm passing it to you all for a little help.

Thanks in advance...

[Maren Mahoney]

I would be suggesting Calling Party Transformations as well. That your TAC engineer doesn't know what the issue is tells me there is more involved in your environment.

Once you have configured the patterns, how are you applying them to the Trunk? Can you provide an example of a Calling Party Transformation (a screenshot), and then also show the CSS with that partition, then show that CSS applied at the trunk? (And I presume you've reset the trunk after application.)

Maren

[Brian Carscadden]

There's nothing more to it than the scenario I presented. I think the TAC engineer was a bit green.

That said ... the trunk is between CUCM and the fax server. The Calling Party Transformation CSS is a configuration option only on the outbound (CUCM to Fax server), so I would not think that is the approach. However simply applying that approach to the outgoing PSTN circuit (MGCP-controlled T1/PRI) that "should" work ... however my tests fail. I'm missing something apparently.

Incidentally TAC also stated I should set the the Transformation Pattern and apply to the trunk.

Recall that my goal is to modify the calling party number coming from the fax server so the when routed to the PSTN the calling party is modified.

[Maren Mahoney]

While it is technically possible to modify the calling party using translation patterns as the call ingresses from the fax server, it would be ugly.

If you have a specific set of calling party numbers that need to be modified, apply your calling party transforms on the PRI as it outbounds to the PSTN. That would be far earlier.

If you insist that you need to modify the calling party as the call ingresses from the fax server, we can talk about how.

Maren

[Brian Carscadden]

I'm not implying that I want to modify the calling party from the fax server; this is what TAC advised. I've noted this to the engineer, and that I've applied it to the PRI ... they're "looking into it" again.

[Roger Kallberg]

I’m with @Maren Mahoney on this, you should be able to modify the calling number by using calling party transformation applied to the MGCP controlled PRI.

Out of curiosity are you doing any transformation of the calling number on the RP or RL/RG levels? If you do you’d need to have the calling party transformation match the number as it appears on the RP level as that’s what the match construct of the transformation would use.

Can you please outline in details of each step along the routing path how the calling number appears and also provide screenshots of a calling transformation and where you’ve applied it on your MGCP configuration?

Also just stating the obvious, but you have I assume reset the MGCP gateway after you have done any configuration changes?

[Brian Carscadden · Accepted solution]

That was my approach as well, but TAC seems confused.

The call that is as noted above, Fax Server -> SIP Trunk -> CUCM -> MGCP T1/PRI -> PSTN

I do not make any number modifications to the RG, however ...

(stepped away to test a theory)

Yep ... okay, found the fix. "Use External Phone Number Mask" must be disabled on the Route Pattern and Route List/Route Group. With Default (or "YES) the Transformation Pattern is ignored.

Thanks for helping solve this one Roger.

[Roger Kallberg]

Glad you found a solution to this. To be clear I was not asking about the call path, I wanted you to outline how the calling number appears at each of the steps in the outlined call path and down to each level of the call processing path in CM. Ie calling number as sent by the fax server onto the SIP trunk, the number as received by CM from the SIP trunk, any matched translation pattern(s) as the call leaves the SIP trunk, number as it appears at the RP level and so on at each step of the entire call processing path. The reason for asking for this is that it would outline if you’re having the match statement on the transformation correctly set.

Having use EPNM set would strictly mean that you do something with the calling number at that level, so based on how and when transformations are applied in CM it would make sense that it didn’t work when you had this set on the RP or RL/RG level(s).

[Roger Kallberg]

Apart from my comment I think it would be appropriate if you were to give helpful votes to the responses you feel got you in the right direction to sort out your situation.

[Brian Carscadden]

Of course. Done!

Thanks again.