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Inbound DDi with max-conn in dial-peer


Hi all,

I need to know if anything can be done about this problem I have with a customer of mine.

They have a DDi number that they want to control the amount of simultaneous calls that come in at any one time based on predefined time periods.

I have H323 gateway with a dial-peer that sends the call to CUCM

I have multiple ToD partitions and CUCM translation patterns that match the inbound DDi and then translates it to a DN as per the time of day

A CUCM translation pattern takes that call and points it at a route pattern

That route pattern sends the call back to the H323 gateway

The call matches a voip dial-peer that has the max-conn configured

The call is re-presented to CUCM and hits another CUCM translation parrtern

The call is presented to an end user phone and rings at the phone

The call is answered and everything appears to be OK except that the user cannot place the caller on hold!

This is only a probelm when hairpinning the inbound call back through the H323 gateway.

The route pattern for the translation patterns that send the call back to the H323 gateway is configured as on-net and the gateway has the IE Redirect ticked.

Any help or advice would be greatly appreciated.



3 Replies 3


Hi Paul,

I am not sure how the customer has managed to make the flow so complex.

Are these two different clusters which we are talking about, is there an ICT trunk between, or do the clusters have an h323 gateway in between as it seems from the call flow, do correct me if i am wrong.

With out looking and the call manager traces and debugs, its very hard to say what will fix the issue.

But do let me know the following:

1. Call manager versions

2. MOH being used is unicast or multicast.

Had a similar issue once, and it was fixed by checking the MTP box on the gateway page.

Please try the same, reset the gateway from cucm page and see if it helps.



Robert Thomas
Rising star
Rising star

Even if you got this setup to work, it would not be scalable or easy to maintain and troubleshoot.  Why do you need to hairpin the call, where is the call comming from?

If the customer is into this kind or akward request, I would look at modyfing phone configuration programatically via AXL with some external time based system.

Hi Kunal / Robert,

Thanks for taking the time to look at this and reply.

My customer should really have bought a basic TDM telephone system as this would have done what they want. CUCM doesnt really fit with the small comanies needs for call processing so I am having to find imaginative ways of getting the call structure the customer wants to work with CUCM.

No multiple clusters, no IP trunks just ISDN30 -> H323 voice gateway -> CUCM

Main DDi should only be able to have:

9 concurrent calls Mo -Fr 8am to 6pm

3 concurrent calls Mo -Fr 6pm to 8pm

2 concurrent calls Mo -Fr 8pm to 10pm

1 concurrent calls Mo -Fr 10pm to 8am

So to do this I need to use ToD partitions but these on there own wont restrict the amount of concurrent calls so the only way I can see of doing this is to create 4 translation patterns for the main DDi and translate to 4 different numbers that are sent back to the H323 gateway so they can be processed through defined dial-peers with the max-conn statement. Call then comes back to CUCM and is sent to its destination.

Main DDi comes in as 5090 so:

Mo-Fr 8am to 6pm translate to 4551; send to H323 gateway with dial-peer voip for 4551 with max-conn 9 and send back to CUCM. On CUCM another translation for 4551 which sends call to Hunt Group 1001

Mo-Fr 6pm to 8pm translate to 4552; send to H323 gateway with dial-peer  voip for 4552 with max-conn 3 and send back to CUCM. On CUCM another  translation for 4552 which sends call to Hunt Group 1001

etc, etc.

I am going to configure CUCM gateway for MTP required and test again tomorrow so hopefully the hold functionality will work and if so I have a working solution. Messy, but works!

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