The example with vovida.org may be a typo :-) The idea is pretty simple. Let's say that I can take on the identity [EMAIL PROTECTED], [EMAIL PROTECTED], and [EMAIL PROTECTED] The system may be able to verify that I can be any one of those but it does not know wish one I want to use for this particular call. The hint can indicate which one I want to use.
If I give a hint that I want to be [EMAIL PROTECTED], the system will no allow this because it is not valid for me. Sorry for the sloppy details in this response but hope it helps, Cullen On 5/15/04 3:53 AM, "Goud, Venkat Ramana (Venkat) ** CTR **" <[EMAIL PROTECTED]> wrote: > Hi Subhash, > The criteria itself is open to implementations but I assume based on the > authentication information proxy need to somehow identify a list of > identities that could be validly associated with that user. For ex, this > could either be a database of its own or a database provided by other > component on which it relies. Otherwise malicious UACs might indicated > false identities in PPI. > In the example if PPI is something like P-Preferred-Identity: "John Doe" > <[EMAIL PROTECTED]>, proxy need to verify that this is not a valid > identity for user fluffy and either it rejects this requests or inserts > [EMAIL PROTECTED] or [EMAIL PROTECTED] The reason the example includes > [EMAIL PROTECTED] might be that the domain being forwarded to is > vovida.org and there might be an implicit trust relationship between > those two. > > There are some valid reasons where proxy might need to ignore PPI and > insert a totally different PAI which has no semblance to PPI at all. > When forwarding requests across domains, proxy might need to insert a > PAI which a user is not aware of or might need to provide a different > PAI to the forwarding domain to provide certain features. > > > -Venkat > > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > Sent: Friday, May 14, 2004 10:21 AM > To: Goud, Venkat Ramana (Venkat) ** CTR ** > Cc: [EMAIL PROTECTED]; [EMAIL PROTECTED]; > [EMAIL PROTECTED]; [EMAIL PROTECTED] > Subject: RE: [Sip-implementors] Interpretation of 'hint' in > thePreferred-Identity > > > > > > > Hi Venkat, > My question is how does the proxy recognize if > the PPI is a valid identity for the user ? From the > example, it seems like > P-Preferred-Identity: "Cullen Jennings" <sip:[EMAIL PROTECTED]> results > in the proxy inserting: > P-Asserted-Identity: "Cullen Jennings" <sip:[EMAIL PROTECTED]> > > In this case, how did the proxy decide that the PPI was a valid or > invalid identity ? Ideally it should have inserted [EMAIL PROTECTED] > but it seems to have inserted [EMAIL PROTECTED] Is it correct to assume > that it did a _full_URL_comparision_; did not find a match; and hence > inserted the closest identity it could find to the one suggested in the > PPI ? Again, in deciding "closest identity" what was the criteria - the > PPI header does not allow the client to suggest which part of the header > is to be used as the hint (display-name or userinfo part or > whatever)...is that left open to implementations ? > > Thanks, > Subhash. > > > > > > "Goud, Venkat > > Ramana (Venkat) > > ** CTR **" > To > <[EMAIL PROTECTED]> <[EMAIL PROTECTED]>, > > > <[EMAIL PROTECTED]> > 05/13/04 06:28 PM > cc > <[EMAIL PROTECTED]>, > > <[EMAIL PROTECTED]>, > > <[EMAIL PROTECTED]> > > > Subject > RE: [Sip-implementors] > > Interpretation of 'hint' in > > thePreferred-Identity > > > > > > > > > > > > > > > > > > I think section 6 is pretty clear on this. PPI is only a > suggestion/request so I guess its up to the proxy as to whether to use > the hint or not. > > If there is a P-Prefferred-Identity header: > > 1) If the proxy recognizes it as a valid identity for that user and if > there is no local policy for the proxy suggesting some other PAI, then > it can use the one in the PPI header. > > 2) If the proxy does not accept the PPI as valid identity for the user > then it may either reject that request or use a PAI constructed based on > its local policies. > > -Venkat > > > > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of > [EMAIL PROTECTED] > Sent: Thursday, May 13, 2004 8:33 AM > To: [EMAIL PROTECTED] > Cc: [EMAIL PROTECTED]; [EMAIL PROTECTED]; > [EMAIL PROTECTED] > Subject: [Sip-implementors] Interpretation of 'hint' in > thePreferred-Identity > > > > > > > Hi, > RFC 3325 states that a proxy may use the P-Preferred-Identity in > an incoming request as a hint to choose among multiple identities that > are configured for a user. The example section shows an example where > the user suggets that he prefers to use the identity [EMAIL PROTECTED] > But the proxy inserts [EMAIL PROTECTED] in the forwarded request. > The RFC does not clearly specify how the proxy should interpret > the 'hint' that is provided. From the syntax of the P-Preferred-Identity > and the P-Asserted-Identity it seems that one should do a URL comparison > to choose the correct PAI header. But from the example, it seems like > either the display-name or the userinfo part is being used to choose the > correct PAI header. > Can someone provide some clarity or point to discussions which > indicate how the 'hint' should be interpreted. Is it that no rules have > been laid down so that it is left to individual implementations ? In > that case, could implementors/authors suggest as to how one would > normally interpret the hint i.e. by comparing which part of the > P-Preferred-Identity header. > > Thanks in advance, > Subhash Nayak > Hughes Software Systems > http://www.hssworld.com > > _______________________________________________ > 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
