Hello Dale, Thanks for the explanation. 305 has 3 contacts. Proxy decided to recurse on first 2 contacts. For some reasons Proxy decided not too recurse on the 3rd contact. Meanwhile, If proxy received 4xx from 2nd contact, (and not all the contacts are recursed) 305 will be forwarded for 305 being lowest class.
Is my understanding OK? If yes, are there specific reasons for proxy deciding not to recurse on some of the contacts? Thanks Karthik On 1/21/09, Dale Worley <[email protected]> wrote: > > On Tue, 2009-01-20 at 22:06 +0530, karthik karthik wrote: > > Hello, > > I request clarrification with redirection. > > Term PCSCF receives 305 with 2 contacts only. > > Term PCSCF initiates a call to first contact and receives 486. > > Term PCSCF recurses to the next contact and again receives 486. > > What is the best response to be forwarded to the originating side? > > I read the statements from 3261, sec 16.7 and not clear about the > decission. > > sub section 4: > > If the proxy recurses on all of the contacts in a 3xx response, > > the proxy SHOULD NOT add the resulting contactless response to > > the response context. > > If the proxy recurses on a 3xx response, it does not add the 3xx > response to the set from which the ultimate response is to be chosen, > but rather adds all the responses to the recursive INVITEs to the set. > > Section 16.7 handles the more complex case where the proxy may choose to > recurse on some Contacts and not others. The Contact headers naming the > contacts which the proxy recurses to are removed from the 3xx, leaving a > shortened 3xx response, which in principle is put into the response set. > In that case, the 3xx response is likely to be the "lowest response > class" in the response set and be the final response sent upstream. > Those rules ensure that the upstream element does not see a 3xx response > containing a Contact that this proxy has already recursed on. > > But in the usual case, the proxy recurses on all Contact headers, and so > the 3xx response is emptied of Contact headers. In that case, it is a > "contactless response" and is not put into the response set. > > Dale > > > _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
