2009/3/14 Scott Lawrence <scott.lawrence@xxxxxxxxxx>: > On Sat, 2009-03-07 at 13:36 -0500, Hadriel Kaplan wrote: >> >> > -----Original Message----- >> > From: sipping-bounces@xxxxxxxx [mailto:sipping-bounces@xxxxxxxx] On Behalf >> > Of Dale Worley >> > Sent: Saturday, March 07, 2009 9:03 AM >> > To: SIPPING >> > Subject: Supporting Multiple Path Routing >> > >> >> Also, separating it into "response from proxy" vs. "response from UA" >> is not that simple, and won't fix that much. There are plenty of >> proxies that represent the ONLY path to get to that UA, and plenty of >> UA's which do NOT represent the only path to get to the user. I think >> what you really want to know is if the request got to the domain >> responsible for the AoR and it got routed within that domain to the >> UA, or not. Right? ISTM the real hard part there is due to the scope >> of the AoR - if it's an E.164 username, the domain is not relevant and >> the scope is bigger than SIP (it's semantically a tel URI), so the >> domain reached doesn't always know if it's really solely authoritative >> for that user or not globally. > > You're right, but I think that there are many cases in which > intermediaries _do_ know what the real situation is but report it in a > way that's ambiguous. If the intermediate device is a PSTN/SIP gateway, > then in at least some cases it can distinguish between: > > * it has attempted to reach the PSTN number it extracted from the > SIP request and gotten a response from the PSTN terminal (no > such number or busy), > or > * it has encountered an error somewhere before reaching that PSTN > terminal (gateway is out of channels, trunk busy from the PSTN) > > Granted that not all intermediate systems can know for every request > whether what they are returning is an end-to-end response or an > intermediate-to-end response. But sometimes they do, and when they do > they should be clearer about it than we find them to be today (some > gateways return 486 when they are out of local DSP resources and have > not attempted a PSTN call at all, for example). I would think this should return a 5xx response (503 to be precise). Aren't those things usually configurable in a GW? Hisham > When they can't be > sure, that should (I think) be returned as an intermediate failure > (because if it really was intermediate, then alternate routes will be > tried to attempt to get an end-to-end result). > > > _______________________________________________ > Sipping mailing list https://www.ietf.org/mailman/listinfo/sipping > This list is for NEW development of the application of SIP > Use sip-implementors@xxxxxxxxxxxxxxx for questions on current sip > Use sip@xxxxxxxx for new developments of core SIP > _______________________________________________ Sipping mailing list https://www.ietf.org/mailman/listinfo/sipping This list is for NEW development of the application of SIP Use sip-implementors@xxxxxxxxxxxxxxx for questions on current sip Use sip@xxxxxxxx for new developments of core SIP
