CUBE situation

Unanswered Question
Sep 22nd, 2010


I am about to make an IP telephony installation (CUCM 7.0) with 3 telecom providers as gateways to PSTN.

Two of them will be connected to one Cisco router (2911) where I will install CUBE (IP to IP gateway). My side will have H.323 signaling, while connection to the providers will  be SIP. Third provider will be connected via PRI interface on 1760 router, signaling to CUCM also H.323.

First 2 telecom providers will provide me with 10 voice channels each on their connections.

Third telecom provider (PRI) will provide me with 30 voice channels.

3 different group of users will be created, each of them with one of providers as default gateway for outside calls.

Here is my problem, if for example first group of users that has all of theirs 10 channels reserved (taken) tries to make a call, will this call be transfered to the second provider, and if this is taken as well, will it be forwarded to PRI link? Of course I will configure route lists and route groups that all users have primary, secondary and tertiary PSTN gateway. two providers on CUBE will be distinguished via prefixes and with dial peers calls will be forwarded to specific provider.

Do you have some suggestions how to configure this, will this work, is my construction viable and what do I have to pay special attention to?

Thank you!

Best regards,


I have this problem too.
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Steven Holl Wed, 09/22/2010 - 10:40

First, from a design perspective, I'd recommend doing SIP between CUBE and CM, so that you can do early offer forced and don't have to require an MTP for calls out the trunk.  With H323 you need to require an MTP for outbound fast start to get early offer to your provider.

You can limit the amount of calls to each provider in several ways, in my decending order of preference:

-Use Call Admission Control (locations) on CM to only allow certain amounts of concurrent calls/bandwidth to each provider.

-Use the 'max connections' command on the CUBE dial-peers to limit the amount of active calls out each peer.

-Have the provider reject calls over a certain value with a certain response, and get the gateway or CM to hunt off that and to the next applicable match.

In all of those scenarios, you'll want to make sure you have each trunk listed in a separate route group in CM.  If you're using the same CUBE for both SIP trunks for hunting the calls to each provider individually, it will get a little trickier, but still can be done.


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