CUCM - Called Transformation Pattern - Outbound on ISDN issue

[mcgeehonjp]

I am trying to get a better grasp on transformation patterns and am having trouble with the transformation of the called number on outbound ISDN call.

I am routing a call through a translation pattern, then to a route pattern and then to a route list and finally to a route group.  The route group terminates at a DS1 circuit. This is an MGCP controlled voice gateway.

On the DS1 interface page on CUCM, I have set the outbound calling and called transformation CSS as seen in the following image.  The CSS Josh-CSS5-TXF1 contains a single partition that itself contains a single called and calling transformation.  The calling transformation works perfectly.  For some reason the called is not matching.

Here is the actual transformation:

And finally, here is the q.931 output on the voice gateway showing the call.  As far as I can see the outbound called number should match and the plan and type are correct.  Any ideas?  The goal is to insert 22 in front of the 500724444, however nothing is happening.  This is an MGCP controlled gateway and circuit.

Dec 17 00:55:05.619 UTC: ISDN Se0/0/0:15 Q931: TX -> SETUP pd = 8  callref = 0x0001
        Sending Complete
        Bearer Capability i = 0x8090A3
                Standard = CCITT
                Transfer Capability = Speech
                Transfer Mode = Circuit
                Transfer Rate = 64 kbit/s
        Channel ID i = 0xA9839F
                Exclusive, Channel 31
        Calling Party Number i = 0x2881, '696968'
                Plan:National, Type:National
        Called Party Number i = 0x80, '500724444'
                Plan:Unknown, Type:Unknown
Dec 17 00:55:05.647 UTC: ISDN Se0/0/0:15 Q931: RX <- CALL_PROC pd = 8  callref = 0x8001
        Channel ID i = 0xA9839F
                Exclusive, Channel 31
QUEBEC-CO-VG1#
Dec 17 00:55:05.647 UTC: ISDN Se0/0/0:15 Q931: RX <- DISCONNECT pd = 8  callref = 0x8001
        Cause i = 0x8281 - Unallocated/unassigned number
Dec 17 00:55:05.675 UTC: ISDN Se0/0/0:15 Q931: TX -> RELEASE pd = 8  callref = 0x0001
Dec 17 00:55:05.683 UTC: ISDN Se0/0/0:15 Q931: RX <- RELEASE_COMP pd = 8  callref = 0x8001

[mcgeehonjp]

I solved it.  I didn't realize that the Transformation pattern is looking for the digits that the Route pattern received, and not what the Route pattern sent.

So, for example, if the route pattern receives 11111 and then changes it to 22222 on its way out to the circuit; the transformation pattern will only match on 11111 and will ignore the changes made by the route pattern.  This is a good reason to not use transformation on a route pattern for PSTN calls or calls that you want to normalize on their way to a specific CO.

[Vivek Batra · Accepted solution]

Thanks for sharing your observation [+5].

Would like to further clarify what you said. Beside digit manipulation at translation pattern level, you have three choices to apply digit manipulation (after it's been applied at translation pattern level) but only one works at a time. 

Route Pattern

Route Group (per Route List)

Gateway

Simple thumb rule is, digit manipulation closer to gateway level will be used. What does this means that if you have applied digit manipulation at all three levels, only gateway manipulation will be used and previous two steps will be discarded.

Similarly if you have applied digit manipulation at Route Pattern and Route Group level, digit manipulation at Route Group will be used and previous (route pattern) will be discarded.

Digit manipulation at route pattern will be used only if no manipulation being done at route group and gateway level.

- Vivek