Regarding your point (2), Party B can be a PSTN number, in which case Proxy can forward the request-uri which will be in tel format to some SIP-PSTN Gateway. Given a tel number, there is a way to may tel to sip urls using e-num service.
Hope this answers your doubts. On 4/25/07, Vikram Chhibber <[EMAIL PROTECTED]> wrote: > In biref, this is how it happens. > If a proxy receives INVITE message and there is a route header after > it has removed its own, then the proxy will use this route header to > forward the request. > > If a proxy receives INVITE message with no route header and the > request-uri's domain it is responsible, then it will replace > request-uri with remote target (B's registered address) and shall send > the INVITE to B. > > If a proxy receives INVITE message with no route header and the > request-uri's domain it is not responsible for, it shall forward the > INVITE using DNS lookup on the domain part of the request-uri (The way > our mails are routed from one SMTP server to another using DNS lookup. > > You need to read RFC-3261 to get into more details. > > On 4/25/07, varun <[EMAIL PROTECTED]> wrote: > > Hi, > > could anybody please answer my queries?? > > > > Thanks > > varun > > > > --- varun <[EMAIL PROTECTED]> wrote: > > > > > Hi, > > > I have some basic doubts: > > > 1> Lets say user A calls B and there is a proxy in > > > between.So the proxy looks at user part of Request > > > URI > > > or at the TO field in Invite request to forward the > > > call. Both ReqURI and To field in this case would be > > > same. > > > 2> When is a tel URI used? > > > > > > 3> When is DNS look up used in Sip call? > > > > > > Please reply. > > > > > > Thanks > > > varun > > > > > > __________________________________________________ > > > Do You Yahoo!? > > > Tired of spam? Yahoo! Mail has the best spam > > > protection around > > > http://mail.yahoo.com > > > _______________________________________________ > > > Sip-implementors mailing list > > > [email protected] > > > > > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors > > > > > > > > > __________________________________________________ > > Do You Yahoo!? > > Tired of spam? Yahoo! Mail has the best spam protection around > > http://mail.yahoo.com > > _______________________________________________ > > Sip-implementors mailing list > > [email protected] > > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors > > > _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
