Overlapping SIP uri with GW prefix

[ciscophonewala]

Hello Techies,

I have registered an ISDN gateway with VCS control with prefix 7. So, when user wants to dial ISDN call, he/she dials 7followed by number and call routes to ISDN gateway which strips of 7 and sends call to public network.

However, when the same user dials SIP URI 743432323@publicdomain.com, the call instead of going to VCSexpressway, it goes to ISDN gateway.

How can I get around to this problem?

thnx

-wala

[Nick Halbert-Lillyman]

You could try changing the priorities of your search rules so that calls to a domain other than your own have a higher priority than the GW prefix.  I woud need to know a little more about your internal dial plan to tell exactly what you need to do, but it sounds like the call hitting the search rule for a prefix of '7' before it's hitting the search rule to send to VCS-Expressway.

[Paulo Souza · Accepted solution]

Hi Wala, welcome to Cisco Support Community!!

You should implementing a dial in VCS that avoid this kind of mismatch. I don't know which search rules and transforms you have configured, but these are some points you should investigate:

1 - The alias 743432323@publicdomain.com should not be routed to the local of VCS Control, if this is happening, you probably have a "Any alias" search rule that points do LocalZone, that is not correct, you should create specific search rules whose patterns match your local registered endpoints aliases

2 - With regards gateway ISDN, you should have a specific search rule to route call to ISDN. For example, for SIP endpoints reach ISDN, you should have a search rule pointing to LocalZone whose pattern is (7\d+)@localdomain.com and replace \1. This will remove only the domain portion of the URI and send only the 7XXXX to ISDN gateway registered to LocalZone. In this case, I am assuming that you have a transform with the pattern ([^@]*) and replace \1@localdomain.com. If you don't have this tranform, you should create another search rules to match ISDN route for H323 endpoints that dial only the number, it would something like this:  7\d+ and route to local zone.

3 - Also, when creating the routes, prefer to use regex than preffix or suffix strings, regex is the best option to avoid dial plan mismatch. Instead of using prefix 7, use regex 7\d+. For example, prefix 7 matches 7654654@externaldomain.com, but regex 7\d+ does not.

4 - There is an important thing to consider when registering ISDN gateway to VCS, mainly when you have VCSe. You should implement a Toll Fraud prevention mechanism in order to avoid external users to use your system as a free telephone system. You can do that by using Call Policy; or using search rules + authentication + Subzones. You may want to take a look at this thread:

https://supportforums.cisco.com/message/3971947#3971947

I hope this help.

Paulo Souza

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