Globalized Dial plan norms & question for CUCM

[Clutz5250]

I'm reviewing e.164 info and it seems I'm getting conflicting answers or I'm simply not digesting things correctly. When it comes to directory numbers in CUCM, having it live on a partition as (example) \+7771230987 is now the norm? So \+ and 10 digits (NANP)?

[Roger Kallberg]

Not sure what you mean by “having it live on a partition as (example) \+7771230987”? What you list as an example of a partition, or anyway that’s how I read what you wrote, is not IMO a partition, it’s a directory number. That said you would normally put your DNs into one partition, so if that’s what you meant that’s right. If it’s something completely different please elaborate?

Having directory number in +E.164 format is nowadays the recommendation and best practice.

[Clutz5250]

Thanks for the response and sorry for the poor wording. The pattern (\+7771230987) was meant to be an example of a e164 directory number that lives on a partition.
I'm currently going through CLCOR material and simply got my wires crossed. Some of the wording in the globalized dialing section seemed ambiguous, and made me wonder about the modern expectation.

[Maren Mahoney]

Note that the + in the dialstring is an indicator that the string is in E164 format.

So, not \+ and then 10-digits. It would be \+1XXXXXXXXXX with the "1" indicating the country code.

And, yes, it is increasingly common to have a dialplan in E164 format with Globalized Call Routing configured. There are many benefits, especially if you are integrating CUCM with another application like MS Teams or Webex. If you are using a SIP trunk to your PSTN service provider, they may request that numbers are in E164 format as well.

Maren

[Clutz5250]

Thanks for the response and insight.
Yea globalized dialing and e164 still feels like a fuzzy/new concept for me. Not something I normally deal with.

[Roger Kallberg]

It cannot really be seen as a new concept as it’s been what Cisco has promoted since about 2009/2010. Also it’s what has been a common thing in most other parts of the world than in USA where I suspect that you live in based on what you wrote in your first post. Back when I studied to take my CCIE in 2010 there was, and maybe still is, a great post about how this operates in CM made by the outstanding Vik Mahli over at CollabCert, but back then he was with IPExpert. If you find it it’s a great source of information. Also the CM SRND is a great source of information about this topic, recommend you to read that part of the document.

[Clutz5250]

I might check that out, thanks! Yea, I've read through a fair bit of the SRND and other sources.
Unfortunately there's only so much i can glean and understand of what's normal and what isn't - in this kind of environment. I've sort of come to terms looking like an idiot if it means removing gaps in my own knowledge. /shrug.

I'm only 3 years into voice, and its all in this environment. What people regard as new or old features is a weird one for me.

[Elliot Dierksen]

As @Roger Kallberg mentioned, I think I got my first exposure to +E.164 stuff during my CCIE Voice/Collab preparation. It is my preferred way to do things now. That doesn't mean you have to use 10 digits for phone DN's. The basic premise is that you normalize (convert to +E.164) any calls (inbound or outbound) before routing, and then localize after they have been routed (like stripping digits down to 4 or whatever). It makes it easy to prevent hair-pinning (calls out and back in) for numbers that are internal. If you structure your dial plan correctly, you can dial the +E.164 of an internal number and it unwraps and routes locally. That has always been a pet peeve of mine.

[Clutz5250]

Thanks for the perspective Elliot. Yea i had some misconceptions about it.

[Roger Kallberg]

IMHO if you don’t use directory numbers in +E.164 format you're in my view missing out on the big benefit of number globalisation. To fully benefit from globalisation in my opinion all called and calling numbers should be presented in full +E.164 format and then adopted on egress to the various formats required by service providers. That said you can still have an overlay that provides the option to make internal calls using a corporate proprietary shorter number scheme by using translation patterns that translate to the full +E.164 number.

[Carlo Poggiarelli]

Agreed but I also see it as a “get ready” way to prepare the customer to a Cloud Solution migration. I’m noticing that large enterprise are moving in that way while traditional dialing is moving to URI dialing so traditional Directory Numbers 5-7 digits in my opinion, are destined to be replaced by URI .

My 2 cents 

Carlo