Hi Mohammed, The answer is: neither. Outbound - strange as it might seem - is for *incoming* requests. It is true that the proxy needs to record-route, in order to route such incoming requests correctly.
outgoing requests that are out-of-dialog (eg MESSAGE, REGISTER itself) are not Record-routed. These messages will not look any different from usual - no instance-id, no Contact, etc Regards, Jeroen ----- Original Message ----- From: Mohammed Hanifa To: Jeroen van Bemmel Cc: [email protected] Sent: Monday, June 26, 2006 5:27 AM Subject: Re: [Sip-implementors] how to forward a response when the proxysupports outbound draft Hi Jeroen, as per the outbound draft, the proxy has to record route so that teh middialog requests can traverse the NAT. will the start line of the mid dialog request contain the instance-id and reg-d of the origincal request that it received? OR the contact uri alone? thanks in adv Mohammed On 6/26/06, Jeroen van Bemmel <[EMAIL PROTECTED]> wrote: Mohammed, see inline Regards, jeroen ----- Original Message ----- From: Mohammed Hanifa To: Jeroen van Bemmel Cc: [email protected] Sent: Sunday, June 25, 2006 8:21 PM Subject: Re: [Sip-implementors] how to forward a response when the proxysupports outbound draft Hi Jeroen, as u told, rport helps in traversing the NAT for UDP. similarly, are there any standard way for TCP, for resp routing thr NAT? OR it has to be taken care of thr implementation. Correct, for TCP this is up to the implementation. I tend to add the 'rport' parameter to the received Via for TCP too (you could remove it again when forwarding the response). for eg, according to the draft, the requet has to record-routed. So,in the record-route, some info about the FD can be maintained. this info can be used to forward the resp. rather than maintaining the state in the element separately, if the info is stored in the record route, it can be accessed while forwarding the resp back. right?? There is no guarantee that the Record-Route will appear in the response (eg error responses, 100 Trying responses) so that is not a good place to put it. The Via header is better (and guaranteed to be present) and i understand that when you mean **state**, you dont mean the regstrar to be transaction stateful. right?? You are right that state does not necessarily imply transaction state, although RFC3261 does say that registrars must be transaction stateful. To support outbound proxies will need to maintain some state (for flows), but they could still be transaction stateless. thanks in adv Mohammed On 6/25/06, Jeroen van Bemmel <[EMAIL PROTECTED] > wrote: Mohammed, outbound only affects request routing. Response routing is not affected, elements are still supposed to remember sufficient state (including e.g. the FD) to be able to route a response back to the same connection as the request came in on For NAT traversal and response routing over UDP, you can use the 'rport' extension Regards, Jeroen ----- Original Message ----- From: "Mohammed Hanifa" < [EMAIL PROTECTED] > To: <[email protected]> Sent: Sunday, June 25, 2006 9:48 AM Subject: [Sip-implementors] how to forward a response when the proxysupports outbound draft > hi all > As per outbound draft, During registration, the aor, its contact is stored > along with instance id, regid and FD of the transport connection. > > assume the registrar is co-located. > > now the registrar gets a new request. normally the contact ip and port for > that > aor will be gotten and the req will be forwarded. Now, the registrar will > look for > the instance id and regid. if it is present, then the corresponding FD > will > be gotten > and the req will be forwarded. > > > UA1 NAT Registrar-colocated-proxy > UA2 > > INV > -------------------------------------------> > INV > > -------------------------------------------------> > 200 ok > > <-------------------------------------------------- > ?? > <------ > > > consider the above scenario. > > on what basis the resp will be forwarded?? now, in order to traverse NAT, > it > should not look into the VIA header? it should somehow get the existing > connection > and then forward the resp. how will it know the existing connection? > > i think, the incoming response will not have any knowledge abt the > instance > id. > should we again get the from uri and do a registrar lookup, inorder to > forward > the resp back to te UA1?? > > sorry if my understanding is wrong. plz clarify. > > thanks in adv > Mohammed > _______________________________________________ > 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
