I have a main office with approximately 250 extensions on a single Elastix server, plus 4 remote sites, each with its own Elastix server and from 2 to 10 extensions. Although the system "works", we want to move to a more fault-tolerant system which "finds" extensions in the system rather than requiring statically defined outbound routes, etc. We would also like to switch to the FreePBX distro instead of the Elastix distro.
So, there are two primary parts to this project:
Part I: Main Office
In the main office, we want to utilize two servers (either in a master-slave or master-master configuration) to provide a high-availability solution with less than 20 seconds of downtime in the event a server fails. We have approximately 25 queues at present with a call volume of approximately 2,000 calls per day and 110,000 minutes of voice time per month. All voice traffic is routed either to another company PBX via SIP over the Internet or via SIP to an ITSP provider.
Part II: Remote Offices
For our remote offices, we are looking to switch from Elastix distro to FreePBX distro and to introduce automatic routing of calls, based on "extension presence" on remote PBX servers. All voice traffic is routed either to another company PBX via SIP over the Internet or via SIP to an ITSP provider.
For awarding this project, we are looking first for a proposal of how to structure our system (which technologies you propose that we use)
Then once the project is awarded, we are looking for a detailed HOWTO on implementation, along with support for initial deployment. We would also want the project winner to be available for future paid support, as needed.
I fully expect that more information is needed for being able to bid, so please ask questions and I will reply with project clarifications.