Newbie question regarding IVR using Asterisk

I have an IVR application that is hosted by a third party provider. The provide the phone numbers, lines, … A call comes in, they pick up, and call my application using HTTP post. I reply with a VXML document, back and forth till the call ends.

I am interested in building an in-house backup system, using Vonage and Asterisk.
My question is whether it is possible to build an IVR application using Asterisk and few Vonage numbers to handle hundreds of simultaneous calls assuming i provide enough bandwidth and cpu power.
I am going to be reading as much as i can about Asterisk in the next few days, but i do not want to invest too much energy if this is not a possible scenario.

My main concern is whether i could be handling multiple incoming phone calls at the same time using a single Vonage number?

thanks for all help.

While it is possible with Asterisk, you may have issues with Vonage. I would imagine that Vonage has a fixed number of lines/channels (say 2 to 3) per account. I doubt Vonage would allow hundreds of simultaneous connections without some type of special account.