This is similar to setting up a huntgroup or dns cycling, where the UAC will try subsequent hosts if request to initial host fails. You need to define policies for the huntgroup, like it will round-robin to the next member in huntgroup if error response is like 503, 408 .., but will not cycle through the list if error response indicates cases, user is busy (486) or a global failure (like 6xx error response)
Sanjay >-----Original Message----- >From: [EMAIL PROTECTED] >[mailto:[EMAIL PROTECTED] On Behalf Of >[EMAIL PROTECTED] >Sent: Thursday, November 16, 2006 3:20 PM >To: [email protected] >Subject: [Sip-implementors] Multiple gateways > >I'm running into this situation: Multiple "PSTN gateway >boxes". If a call is to be routed to a PSTN line, how do I >send it to a gateway in an intelligent way? By that, I mean: > >- If the call is sent to gateway 1, and it has no free ports, and > (most likely) rejects the INVITE with a 503, the call will be sent > to gateway 2, etc. > >- Similarly if gateway 1 is unreachable, which presumably appears as a > 408. > >- But if the call receives an error response which indicates an error > condition at the far end of the PSTN (e.g., 486), do not retry the > call on the next gateway. > >- Be organized as a SIP forking operation of some sort so that it can > be integrated as one fork of an ordinary call routing situation. > >Ordinary SIP serial forking does not do this correctly, nor >does making the IP addresses of the gateways alternative A >records for a DNS name. I'm thinking that the only workable >solution is to treat expanding "[EMAIL PROTECTED]" into >"[EMAIL PROTECTED]", "[EMAIL PROTECTED]", and "[EMAIL PROTECTED]" as a >proxy operation with a particularly complex algorithm for >building the target set. > >Does anyone have a better solution? > >Dale >_______________________________________________ >Sip-implementors mailing list >[email protected] >https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors > _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
