After talking with Juha, I think this is the best compromise. I think an operator who really wants clients to connect with only one proxy can configure a single DNS name for the outbound proxy, and then give multiple DNS (SRV or A, depending upon how you want to play) records for the details of that single name.
Joel Francois Audet wrote: > Let me try to summarize where we are at with the draf-ietf-sip-outbound > thread, and let's try > to conclude. > > The current text says the following: > > At configuration time, UAs obtain one or more SIP URIs representing > the default outbound-proxy-set. This specification assumes the set > is determined via any of a number of configuration mechanisms, and > future specifications can define additional mechanisms such as using > DNS to discover this set. How the UA is configured is outside the > scope of this specification. However, a UA MUST support sets with at > least two outbound proxy URIs and SHOULD support sets with up to four > URIs. > > For each outbound proxy URI in the set, the UAC SHOULD send a > REGISTER request using this URI as the default outbound proxy. > (Alternatively, the UA could limit the number of flows formed to > conserve battery power, for example). UAs that support this > specification MUST include the outbound option tag in a Supported > header field in a REGISTER request. Each of these REGISTER requests > will use a unique Call-ID. Forming the route set for the request is > outside the scope of this document, but typically results in sending > the REGISTER such that the topmost Route header field contains a > loose route to the outbound proxy URI. > > What Juha is worried about is that there is enough wiggle room in there > that some UAs will not register with the minimum of 2. It is true > that it is unclear if the text about battery life was meant to allow > for not registering with all the entries in the route set, but still > keep the minimum of two, or not. > > I propose is that the text would look like this: > > At configuration time, UAs obtain one or more SIP URIs representing > the default outbound-proxy-set. This specification assumes the set > is determined via any of a number of configuration mechanisms, and > future specifications can define additional mechanisms such as using > DNS to discover this set. How the UA is configured is outside the > scope of this specification. However, a UA MUST support sets with at > least two outbound proxy URIs and SHOULD support sets with up to four > URIs. > > For each outbound proxy URI in the set, the UAC SHOULD send a > REGISTER request using this URI as the default outbound proxy. > (Alternatively, the UA could limit the number of flows formed to > conserve battery power, for example). If the set has more than one > URI, the UAC MUST send a REGISTER request to at least two of the > default outbound proxies from the set. UAs that support this specification > MUST include the outbound option tag in a Supported header field in a > REGISTER request. Each of these REGISTER requests will use a unique > Call-ID. Forming the route set for the request is outside the scope of this > document, but typically results in sending the REGISTER such that the > topmost Route header field contains a loose route to the outbound > proxy URI. > > I think this is reasonable. Basically, what this boils down to is very > simple: > is the minimum number of registration for a proxy set that is bigger than one > 2 or 1. > If you are against this proposal, it it is presumably because you believe > a UA should be allowed to use only ONE proxy from the set and ignore the > second one. > > I'd like to get opinions from the list, and close on the issue. > > > > > _______________________________________________ > Sip mailing list https://www.ietf.org/mailman/listinfo/sip > This list is for NEW development of the core SIP Protocol > Use [EMAIL PROTECTED] for questions on current sip > Use [EMAIL PROTECTED] for new developments on the application of sip > _______________________________________________ Sip mailing list https://www.ietf.org/mailman/listinfo/sip This list is for NEW development of the core SIP Protocol Use [EMAIL PROTECTED] for questions on current sip Use [EMAIL PROTECTED] for new developments on the application of sip
