is there a way to configure a router to avoid E1's being bottlenecks?

[EnriqueFornes]

This is a theoretical question is for a college assignment. I want to connect international IP inbound calls to a router in building A, this router will be connected to 4 PSTN E1's (Europe) going to a PABX in building B, that host the ACD and distributes the calls to the contact center agents. Now, if the 120 DS0's (4 E1's) are in use and a new international IP inbound call arrives to the router in building A, he will not find a voice circuit to route the call to the PABX in building B, so it should send a busy tone to the caller. What I'm trying to see is, if the router in building A can place this new call in queue until a PSTN 64 kbps DS0 channel (from the 4 E1's) is available, routing this call through this channel to the PABX in building B in order to reach an agent, and how it should be configured. Hope my question is clearer. Thanks, Kike.

[Nathan Spitzer]

This is the wrong forum for that question as you are knee-deep in VOIP-land with that question. I would ask this in the IP Telephony forum.

Second, please provide more information, such as:

1) What model Router

2) What IOS level and feature-set

3) What kind of PBX, including model/manufacturer and software revision

[EnriqueFornes]

Nathan, thanks for your prompt answer. It's a theoretical question is for a college assignment. I have not decided yet which router or PBX should be used, I'm just trying to see if the configuration for a contact center: a broadband FR access going to a router, going to 4 E1's, going to a PBX with ACD, going to a contact center has a bottleneck in the 4 E1's (120 DS0's). I mean, if the 120 voice circuits are in use and a new call arrives, can a router (which one?) put it in queue until a voice channel from the 4E1's is available, routing the new call through this channel to the PBX ACD in order to reach a live agent, or the caller will receive a busy tone (or go to a VM)?

BTW, which is the URL for the IP telephony forum, I didn't find it.

Thanks, Kike.