You wrote: > In general, I think we have learned that we should help > people with debugging distributed systems with distributed > responsibility, as otherwise they'll either struggle or > invent private mechanisms to include this information. (See > SER for the the latter.)
If we are not careful here we end up back in the issue of responses being significantly larger than the request sent on a particular hop, and therefore the old problem of what happens on UDP when this occurs. Regards Keith > -----Original Message----- > From: Henning Schulzrinne [mailto:[EMAIL PROTECTED] > Sent: Saturday, July 07, 2007 1:06 PM > To: Paul Kyzivat > Cc: [email protected]; James M. Polk > Subject: Re: [Sip] Re: Conveyance -08 and Geolocation-Error header > > > On Jul 6, 2007, at 11:24 PM, Paul Kyzivat wrote: > > > Is it really reasonable to expect a proxy that inserts a > location to > > remember what location it inserted, in enough detail to > diagnose why > > it might have been messed up? I presume it would have to > reconstruct > > what the location would have been based in information in the > > response. It may not be possible to reconstruct the exact > same value, > > because the UAC may have moved in the meantime. I guess the > inserted > > location would have to be by reference, but the URL of the > reference > > may itself not be easily reconstructed, and multiple > queries of it may > > not return the same result. > > > > IMO it would be much clearer to include the location itself in the > > response. And if the location had been passed by reference, > it might > > be better to pass it by value in the response, so that there is no > > possibility of the value changing. > > > > I tend to agree that this would be better. The > reference-to-value translation may not always be feasible: If > a proxy inserts a location reference and a downstream proxy > finds a problem, it can't insert a value (except by the data > URL mechanism I have been mentioning...). > > > > OTOH that might result in divulging the location to nodes > upstream of > > the one that included it. If it was passed by reference > then the node > > that had inserted it could remove the reference in the > response. But > > if it is passed back by value that isn't allowed. > > > > The alternative is that the proxy will have to retain the location > > until the completion of the transaction. Maybe that's ok, > but if its > > only to diagnose an occasional glitch I get it doesn't get done. > > My assumption was that most locations will be inserted by the > UAC rather than a proxy. In those cases, retaining the > information is probably not a big deal, since the UAC will > generally only have one. > > In summary, I think returning as much information about the > erroneous location information as possible seems best, i.e., > both the location information and the party that inserted it. > This avoids the "who the heck put that bogus location > information in there?" problem. > > In general, I think we have learned that we should help > people with debugging distributed systems with distributed > responsibility, as otherwise they'll either struggle or > invent private mechanisms to include this information. (See > SER for the the latter.) > > > > > > Paul > > > > > > _______________________________________________ > Sip mailing list https://www1.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://www1.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
