Unity Connection with overlapping number in multisite

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May 5th, 2010
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Hi All,

we have configured CUC with CUCM in multisite with overlapping extension. Everything works as expected, like MWI, and site to site dialing with access code to reach to the right subscriber.

now we notice some issue with this design. Default CUC AA allows caller to dial an extension at any time. let's say there are two duplicate extensions in two diffferent sites. when caller dial the extension at the begining of AA to reach to userB in siteB, userA in siteA phone willl ring. because in voice port CSS in CUCM, siteA partition is the first partition.

the other solution would be seperate port and port group per each site, but it is not scalable and it is not feasible for more than 20 sites.

any suggestion would be very appreciated.


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William Bell Wed, 05/05/2010 - 12:35
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Without getting into all of the details, you would still need to deal with some form of separation using Unity partitions/search spaces. Just so you can give folks the abbreviated dialing experience in an overlapping dial plan. That being said, I always recommend to use a uniform convention for station line allocation. In North America, I always assign 10-digit phone numbers to IP phone lines. I always assign 10-digit numbers to VM user extensions (in Unity Connection). In CUCM I use translations to provide the abbreviated dialing experience that users prefer. In Unity Connection I use the Alternate Extensions to accomplish the same thing. In both applications I leverage tenant specific partitions for the abbreviated patterns.

For Unity Connection the idea is that a caller can enter an abbreviated number and Unity Connection is smart enough to find the mailbox using the abbreviated number. However, whenever Unity does a transfer it will use the primary extension (which I always set to 10-digits). In North America, you can easily ensure by using 10-digits that the core of your dial plan is free from overlap/conflicts. You still have to deal with the "edges" with abbreviated dialing standards since end users are, well, picky.




alex goshtaei Wed, 05/05/2010 - 13:45
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thanks for your nice reply.

but not all users are using DID. some of them are using only four digit extension. should I still make 10 digits extension for those users?

William Bell Wed, 05/05/2010 - 14:03
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I do. in the nanp, if you use a 0 or a 1 in the first digit position of the NPA or NXX then you are guaranteed the number will not be assigned as a geographic or special purpose number.

So, you could assign 703-101-4231 to a station line and it will be unique. where as 703-201-4231 would present a problem unless you owned that DID of course.




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