In all of section 8, the only reason I find of why things are changed is
"For media steering purposes, B2BUAs in intermediate domains need to modify the IP address c-lines and the port in m-lines." Even this one line leaves me confused about what intermediate domains are in the deployment cases where this happens and if we are talking about email style address or e.164 style addresses. What an example is of a deployment where things like this happen and why the middle (not the end domains) do the media steering. When I ask this of example people give me, if often turns out what is really wanted is not media steering but the middle to be able to hide the fact that they actually delivered the call to a third provider for PSTN termination.
Pretend 4474 does not even exist for a minute. I don't think it is unrealizable of me to ask what the problem is we are trying to solve. Saying 4474 is does not solve the problem may or may not be true but we are unlikely to have a good conversation about about what we should do until we understand what we are trying to accomplish.
On Mar 31, 2009, at 7:00 PM, DRAGE, Keith (Keith) wrote:
Cullen wrote: > The thing I keep asking is can we make a list of reason why > SDP and headers get changes and in what scenarios they do > this. I think it will be hard to sort how to fix this without > being clear what needs to be fixed. > Isn't that the function of the text that was placed in section 8 of http://tools.ietf.org/html/draft-elwell-sip-e2e-identity-important-03 If it is not, then what do you think is missing. regards Keith > -----Original Message----- > From: [email protected] [mailto:[email protected]] On > Behalf Of Cullen Jennings > Sent: Tuesday, March 31, 2009 11:32 PM > To: Jiri Kuthan > Cc: [email protected]; Francois Audet > Subject: Re: [Sip] francois' comments and why RFC4474 not > used in the field > > > On Mar 28, 2009, at 2:02 PM, Jiri Kuthan wrote: > > > > > I'm worried this is only a wishful thinking. While > perfectly logical, > > still even in such constrained setups some bizzar ALGs do in my > > experience appear in the middle, change SDP and make thus > the identity > > worthless. > > The thing I keep asking is can we make a list of reason why > SDP and headers get changes and in what scenarios they do > this. I think it will be hard to sort how to fix this without > being clear what needs to be fixed. > > For example, one of the things we might want to say is > something like: > the Phone is behind a NAT and connects to it's proxy / > registrar for its' domain. That proxy/b2bua whatever mucks > with IP/ports in the SDP for NAT traversal. Then we could ask > if 4474 is broken in this case or not and what might be a > good way of solving the problem of having UAs behind NATs. > > Cullen <in my individual contributor role> > > _______________________________________________ > Sip mailing list https://www.ietf.org/mailman/listinfo/sip > This list is for NEW development of the core SIP Protocol Use > [email protected] for questions on current sip > Use [email protected] for new developments on the application of sip >
_______________________________________________ Sip mailing list https://www.ietf.org/mailman/listinfo/sip This list is for NEW development of the core SIP Protocol Use [email protected] for questions on current sip Use [email protected] for new developments on the application of sip
