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
