From: "Jim Risler" <[EMAIL PROTECTED]> I am interested in this topic because of call centers attempting to utilize SIP need to have failover options that work seemlessly.
1) UA detects failure and switches to another server 2) Server synchronization - Register clients are sychronized between a group of servers 3) Gateway survivability - That is if one gateway goes down, the UA client can re-establish the call to another gateway The problem we are currently discussing is really only applicable to your item 3. And it turns out that the difficult case is not when a gateway goes down. When a gateway goes down, its failure can be detected at the IP level and the upstream agent can use RFC 3263 mechanisms to fall back to an alternative destination address. But if the gateway is only congested, 3263 mechanisms do not help. In regard to item 1, we've discovered that providing more than one server in SRV records for the proxy domain name works well. In regard to item 2, that is more complicated but quite feasible. See the "High Availability" feature of the sipX open-source proxy for an example: http://sipx-wiki.calivia.com/index.php/High-Availability_Installation and links therefrom. Dale _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
