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?