I've done quite a bit of research/reading on SIP trunks (including a great Cisco Press book on the subject), and have a design question.
A customer with 20+ remote sites in smaller areas is deploying a Cisco voice solution, and we initially were hoping to deploy a centralized SIP trunk solution through the main site, and use SIP/SCCP signaling over the WAN to the remotes. So (in my thinking), only the main site would need to support SIP trunking from the carrier.
The carrier (AT&T) informed me that they couldn't support this, since the remote sites were not in "rate centers", and that they didn't support direct SIP trunking themselves. Put simply - they claim we can't do centralized SIP trunking unless each/all of the remote sites COULD support SIP trunking from the carriers themselves. The reason given had to do w/ 911 regulations.
Can I get some clarification on this issue? Is it only possible/practical to realize the benefits of centralized SIP trunking if ALL of the locations are within larger metro areas that could support SIP trunking directly from the carrier?
Thanks again, and reference links are always appreciated.