Actually, on second thoughts, you should get an ICMP error when you attempt to send the ACK to the IP/port that was down. This should result in you resending the ACK to another IP/port from the DNS list? Venkatesh
On 6/16/05, Isaac Dudy <[EMAIL PROTECTED]> wrote: > > What will happen if the UA works with outbound proxy farm, so the UA > sends the INVITE to a FQDN which resolved to all the proxies in the > farm. The first proxy is down so the INVITE transaction is done through > the second proxy. Now the UA wants to send the ACK so it has the same > FQDN as the INVITE and the ACK will go to the first proxy again. My > assumption here is that UA that works with outbound proxy always sends > all transaction to the outbound proxy regardless of other routing > information that arrives in the 2xx on the INVITE, maybe my assumption > is wrong, please advise. > > > Thanks in advance, > David Isaac. > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Dale > Worley > Sent: Thursday, June 16, 2005 7:01 PM > To: [email protected] > Subject: RE: [Sip-implementors] Resolving in ACK request > > That's true, it could happend. But if you don't put IP addresses in as > the hosts in Record-Route's, you should use names that preferentially > resolve to the IP address of the host adding the Record-Route. Section > 6 of RFC 3263 discusses a clever way to accomplish this. If done right, > the chances of an attempt being made to send to a down server are > greatly reduced. > > Dale > -----Original Message----- > From: Venkatesh [mailto:[EMAIL PROTECTED] > Sent: Thursday, June 16, 2005 11:33 AM > To: Dale Worley > Cc: [email protected] > Subject: Re: [Sip-implementors] Resolving in ACK request > > > I think this scenario happens if all the RR headers that got added by > proxies were FQDN's that resolved to multiple IP addresses (per section > 16.6 of 3261 this is possible, as the RR header MUST resolve to the IP > address/port of this element that or a suitable stand in). On receipt of > the 200 OK, the UA constructs the route set which is a set of FQDN's. It > builds the ACK. It uses the Route set to send the ACK. This results in > the UA having to do a DNS lookup. The response returned by DNS could > result in the UA choosing an IP address/port of a proxy that is down. > _______________________________________________ > Sip-implementors mailing list > [email protected] > http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors > ______________________________________________________________________ > This email message has been scanned by PineApp Mail-Secure and has > been found clean. > > > > _______________________________________________ Sip-implementors mailing list [email protected] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
