[cisco-voip] Local route group with CFA and other stuff

[Roger Wiklund]

Answering my own question.

You can add the same SIP trunk multiple times with the same IP,
simulating a H.323 gw setup for example with local gateways in each
country. What you need to do is to create a new SIP Security Profile
and changing the incoming port for each "virtual" SIP trunk.

Then in the CUBE you need to setup dial-peers for each number range
and send it to the callmanager but on a different port.

Example:

dial-peer voice 10 voip
Calls to CUCM (SE numbers)
destination-pattern 100.
session target ipv4:192.168.1.10:5070

dial-peer voice 20 voip
Calls to CUCM (UK numbers)
destination-pattern 200.
session target ipv4:192.168.1.10:5071

This way you can have multiple "virtual" SIP-trunks to the same IP
address (CUBE). Now you can use a unique Called/Calling party
transformation CSS per "virtual" SIP trunk. Very useful for Extension
Mobility for example.

If SE user roams to UK, he will use the UK device pool and device CSS
etc. So therefore route out via the UK "virtual" SIP trunk. But
because he still has a Swedish number, I want to normalize the numbers
to the UK switchboard number. Very easy now with "virtual" SIP trunks
by just applying Calling Party Transformation CSS in the Trunk for
outbound calls.

Without "virtual" SIP Trunks you only had one SIP trunk configured,
and thus shared among the countries, very difficult to normalize in a
roaming scenario.

Hope this helps someone.

Regards
Roger

On Wed, Jun 8, 2011 at 5:01 PM, Roger Wiklund <roger.wiklund at gmail.com> wrote:
> In the old days of (IP)PBX and before LRG:
>
> Phone A calls Phone B (onnet). Phone B has CFA to mobile phone. The
> call to the mobile phone is sent via Phone B's gateway.
>
> After LRG, same scenario, The call to the mobile phone is now sent via
> Phone A's RG-gateway specified in the DP.
>
> This of course poses a problem, especially if A and B are in different
> countries. You cannot call a local mobile number in country B from
> country A.
>
> Solution: Globalize called number to E164 and then normalize on each
> gateway. This is all fine and dandy, also simplifies TEHO, AAR etc
> when the called number is already in the correct format in conjunction
> with LRG.
>
> Now to the problems.
>
> CFA problem: I know there is a question of "who pays for the CFA". But
> before LRG and all PBX configurations that I have encountered handles
> this the "old" way. Phone B paying.
>
> With the "old" solution, the call is at least a local call within the
> country. With the new solution, the call is an international call if A
> and B are in different countries. Also lets say that Phone A is not
> even allowed to make an international call, then CFA won't work at
> all.
>
> Normalization problems:
>
> If im in Sweden and call US I would dial: 001xxxxxxxxx
> If I dial a number outside my area code I dial 018xxxxxxx for example
> (018 being the area code)
> If I dial a number in my area, I can skip the 0 and just dial the
> local number 5 to 8 digits in length for Stockholm.
>
> Now best practise is to send the numbers to the PSTN like this,
> depending on where I call. It's easy to accomplish this with called
> party transformation patterns to strip the E164 +46 +1 etc and prepend
> 00, or 0 etc.
>
> Now this assumes that I have local gateways at each site. Because If I
> have a gateway in Stockholm and one in London, I need to have
> different transformation patterns to normalize.
>
> Now what will happen if I have a central SIP trunk instead of local
> gateways in each country. My SIP trunk provider only has one trunk,
> and on that trunk there are "virtual" gateways if you will. I.E public
> phone numbers for Sweden, UK, Germany etc. The SIP trunk provider
> determines what location to use based on the calling number. So If i
> place a call from Sweden to US for example, it will identify based on
> the calling number that this call is from Sweden, and then it will
> apply the Sweden dial plan and rates etc in the PSTN.
>
> Now as I only have one SIP trunk, I can only apply one transformation
> patterns. As far as I see it, there is no way to normalize the numbers
> now.
>
> So just because I use a central SIP trunk, I can no longer use LRG. So
> I need to create route patterns over and over again for the same
> country. It's like hey we have this cool new features, but you cannot
> use them because you use a SIP trunk.
>
> Have you encountered this problem or something similar? Any nice
> workarounds or something like that that I have missed.
>
> Thanks
>
> /Roger
>