[cisco-voip] Adding area code to local calls and digit manipulation at route list/route pattern level

[Gary Parker]

Afternoon all, I’ve got a problem I’ve been struggling with for a few days now. It’s bound to be something simple I’ve forgotten from my CCNA Voice days (a long time ago!).

I’m running CUCM 12.5 SU4 with GBNP 1.1(31) and 2921 voice gateways operating as CUBE with IOS 15.5(3)M2 in the UK

Background:
I’m in the process of migrating our outbound PSTN dialling from our Virgin Media Business PRI circuits to SIP trunks provided by Gamma. The problem I’ve encountered is with local rate calls with no area code. Our PRIs will happily route outbound six digit dialled numbers but the SIP trunks will not. I suspect this is a common problem, and will only become more common in the UK as Ofcom removes the obligation on TSPs to provide local dialling:

https://www.ispreview.co.uk/index.php/2021/04/ofcom-will-stop-requiring-uk-phone-providers-to-offer-local-dialling.html

Problem:
I though this would be a relatively simple task of adding Prefix Digits (Outgoing Calls) of my area code (01509) to all calls matching the LOCAL route filter using a Route Pattern. At first glance, Dialled Number Analyzer shows that Dialled Digits of eg. 9112233 gets transformed to Called Party Number of 01509112233

	• Results Summary
		• Calling Party Information
		• Dialed Digits = 9112233
		• Match Result = RouteThisPattern
		• Matched Pattern Information
		• Called Party Number = 01509112233
		• Time Zone = Etc/GMT
		• End Device = Lboro_SIP_Test
		• Call Classification = OffNet
		• InterDigit Timeout = NO
		• Device Override = Disabled
		• Outside Dial Tone = NO
	• Call Flow
	• Alternate Matches

However calls via the SIP TSP fail with a 404 as the dialled number is still “123456” when I look at debug on the voice gateway.

Looking more closely at the DNA output it appears that the post-transform Called Number at the Route Pattern level isn’t being passed to the Route List:


	• Call Flow
		• Route Pattern :Pattern= 9.@
			• Positional Match List = 
			• DialPlan = United Kingdom Numbering Plan
			• Route Filter
			• Require Forced Authorization Code = No
			• Authorization Level = 0
			• Require Client Matter Code = No
			• Call Classification = OffNet
			• PreTransform Calling Party Number = 445566
			• PreTransform Called Party Number = 9112233
			• Calling Party Transformations
				• External Phone Number Mask = YES
				• Calling Party Mask = XXXXXXXXXX
				• Prefix = 
				• CallingLineId Presentation = Allowed
				• CallingName Presentation = Allowed
				• Calling Party Number = 
			• ConnectedParty Transformations
				• ConnectedLineId Presentation = Default
				• ConnectedName Presentation = Default
			• Called Party Transformations
				• Called Party Mask = 
				• Discard Digits Instruction = PreDot
				• Prefix = 01509
Correct here ->			• Called Number = 01509112233
		• Route List :Route List Name= Lboro_SIP_Test
			• RouteGroup :RouteGroup Name= LBORO_SIP_Gamma-TEST-RG
				• PreTransform Calling Party Number = 445566
Incorrect here ->		• PreTransform Called Party Number = 9112233



Why are the transformations I make at the Route List level being dropped when the call gets to the Route Group? I understand that Route List/Group transformations override Route Pattern transformations, but I’m not doing any transformations at the Route List/Group level beside Discard Digits, GBNP: PreDot. This is necessary as, again, although PreDot is applied at the Route Pattern level the ‘9’ is back again when we get to the Route Group.

FYI, I’m using "Use Calling Party's External Phone Number Mask” to correctly apply the area code to CallingPartyNumber in outgoing calls, but that’s not reflected in DNA. External calling party number is always 01509XXXXXX

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/-Gary Parker----------------------------------f--\
|     Unified Communications Service Manager      |
n      Loughborough University, IT Services       |
|     tel:+441509635635 sip:gary at lboro.ac.uk      o
|        https://www.osx.ninja/pubkey.txt         |
\r----------------------------------------------d-/