HI, I was asking about the protocol mechanism , not high availability . Even in this case ,How will the backup inform the ua that it is the master ? -mahesh
-----Original Message----- From: Avasarala Ranjit-A20990 [mailto:[EMAIL PROTECTED] Sent: Friday, November 04, 2005 2:46 PM To: Mahesh Govind; Dale R. Worley; Sip-Implementors Subject: RE: [Sip-implementors] Out of service in sip.. Hi I don't think any proxy currently supports this functionality. But using a master/backup high availability kind of mechanism, there could be a master and backup proxy servers. Here the slave proxy gets periodic updates from master, so that master and backup are always in sync with respect to subscribers' data and CDRs. In the event that master goes down, the backup can become master and send notification to User agents that it is the master proxy. Ranjit -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Mahesh Govind Sent: Friday, November 04, 2005 10:04 AM To: 'Dale R. Worley'; 'Sip-Implementors' Subject: RE: [Sip-implementors] Out of service in sip.. HI, These are response code , what I wanted to know that ,How a proxy tells a ua in advance that it is going down .Also how can it tell ua ,"instead of me contact this proxy", .If this can be done this will help thin cell phone clients to be reconfigured automatically , where it may not have full dns look up capability . -mahesh -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Dale R. Worley Sent: Friday, November 04, 2005 1:07 PM To: Sip-Implementors Subject: Re: [Sip-implementors] Out of service in sip.. On Fri, 2005-11-04 at 09:46 +0900, Mahesh Govind wrote: > What is the mechanism by which a ua can know the proxy is out of > service . Is there any mechanism by which a proxy can tell ua that it > is going out of > service and come back after some time or use another proxy as the > proxy . Response code 503 looks like what you want: 21.5.4 503 Service Unavailable The server is temporarily unable to process the request due to a temporary overloading or maintenance of the server. The server MAY indicate when the client should retry the request in a Retry-After header field. If no Retry-After is given, the client MUST act as if it had received a 500 (Server Internal Error) response. A client (proxy or UAC) receiving a 503 (Service Unavailable) SHOULD attempt to forward the request to an alternate server. It SHOULD NOT forward any other requests to that server for the duration specified in the Retry-After header field, if present. > If ua uses DNS look up this case will not arise . > But if some thin client is not doing the dns srv how can it know in advance If a UA doesn't do DNS, it must be dependent on some sort of infrastructure (PBX, service provider, etc.) which presumably is responsible for provisioning the UA with an outbound proxy. Dale _______________________________________________ Sip-implementors mailing list [email protected] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list [email protected] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list [email protected] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
