Looking at a CUCM that has an LDAP integration. DNs in CUCM are 4 digits (matching the last 4 of the DID), while telephone numbers in LDAP are 10 digits and can't be modifieed to use only 4. As a result, users telephone numbers in the corporate directory have their full 10 digit numbers. I thought about trying to find a way to do a translation pattern (so anything user dialing AAABBB1234 would drop the first 6 and only dial the last 4) where I would see how many of the DIDs I could match. But I was wondering if there is a better way to do this. I didn't want to convert their accounts to local accounts on the CUCM. And while I know I can apply a mask on new users as their imported, I didn't recall if that worked on existing users.
Well, one option is to map the LDAP ipPhone attribute to CUCM instead of telephoneNumber; that would allow you to pull in four-digit extensions as is.
My recommended approach would be to change at least LDAP, ideally CUCM’s Call Routing design as well, to the +E.164 standard, e.g. +14045550100. If you do it only in LDAP and leave the CUCM design alone you would then assign an +E.164 Alternate Number directly on the DN or create Translation Patterns to match the globalized form of the pattern and strip it down.
Directory Lookup Rules are a third option but only help Jabber / Webex app.
If you truly want to stay with four digit directory numbers in CM I would recommend that you use the option to have ipPhone number field in AD synced into the telephone field in the user objects in CM. Otherwise the recommendation would be to rework your existing number structure in CM to use full +E.164 numbering scheme as that’s much more scalable. You can still allow the users to call each other by short numbers, either by an overlay of translation pattern(s) or configuration on the individual directory numbers. Where my personal opinion would be to go with the TP overlay, but your preference might be different. It all comes down to what you prefer and are comfortable with.
Thanks for the replies. I'll see if I can get access to AD to review, but I believe they're formatted a +E.164 already. I'll try adding the alternate number for a few DNs and reworking a few lines in IT to use the +E.164 format along w/ a TP and see which works better for us.