Application Dial Rules and Call Routing with Remote Destinations

Yesterday we had an issue with dialing.  To put it plainly, a 10 digit number was being stripped to 7 digits for no apparent reason until right towards the end of the day when we discovered the Application Dial Rules for some reason applied to RD/RDP?!?!?  Yes, you heard that right, the application dial rules for the old school Unified Personal Communicator and other programs that could run with CUCM and make calls. 

The story starts off with my changing my cell phone number, actually, it goes before that but I figure we can start there.  I changed my number to a local number since I was still using my hometowns number from when I was in my army days.  I just never changed it and left it as is since it was considered a local call for my mother and she doesn't have long distance.  Anyways, I updated the Remote Destination to the new number and all of a sudden I wasn't getting calls from my desk phone on my cell phone.  Others had some minor issues but we blamed CUCM 8.5 at the time.  Now, we are on CUCM 10.5(2) so there are no excuses as to why something wasn't working that has been around for so long.

We opened up the gateways and watched the traffic from CUCM come in via H.323 and saw that my number was being presented to the gateway as 7 digits instead of 10.  This didn't make any sense since we checked the following:

1. Translation Patterns for crazyness
2. Route Patterns
1. We even made a explicit RP for my cell phone and no change...
3. Gateway Configs
4. Line and CSS config
5. Device Pools and Transforms

All of these checked out and left us scratching out heads.  Dialed Number Analyzer (DNA) was worthless in showing us the problem since it isn't going to show you transformations done at the application dial rule area. Towards the end we took a look at Application Dial Rules and saw some in there.  We use Jabber and as of now there is no reason to use the ADR(Application Dial Rules) with 10.5(2) unless you got some really old clients still in use. 

We noticed that there were about 7 rules and 2 of them could have been a match for my cell phone ANI.  I was basically being stripped down there then passed to another route pattern for Waco 7 digit dialing and dumping because of this.  Also, in case you were wondering, Waco does still use 7 digit dialing locally.  Additionally remote destinations use en-bloc dialing so urgent priority and other patterns that could match beforehand are not even considered.  All in all, these rules were for some weird reason, affecting remote destinations.  Please keep this in mind if you ever run into the same issue.

Moving on to another topic, I talked about en-bloc dialing.  I figured for those that may not know what en-bloc is I would go ahead and explain.  There are two different types of dialing.  The first is digit by digit in which the CUCM receives the numbers one by one and analyzes them against both the route patterns and internal directory.  This is common on SCCP phones and now, Type B SIP phones also support this via KPML(Keypad Markup Language).  The second method is en-bloc which cell phones and all SIP phones are capable of doing.  Basically, it sends the entire string all at once to the CUCM and then a match is determined.  In this case, urgent priority is disregarded since CUCM was never given the chance to look for a longer match.

So what is urgent priority you might ask?  Urgent priority is a checkbox that can be set on DNs and route patterns.  Translation patterns are always urgent priority.  This feature basically forces a route even if there are possible longer matches.  Usually you will see this used for emergency features such as 911 and is why you should be using an "8" to dial an outside line and not a "9". 

Well that is all I got for today.  I apologize if I haven't posted much lately, I been busy finishing up the NP Voice track since it goes end of life this year.  I figured I need to go ahead and get the cert instead of studying all new material that I could better learn on the job when and if it comes around assuming I don't already it.  I hope this post has been helpful and have a great day!