Hi Hadriel, I don't disagree with you.
However, there are examples where we do this kind of restrictions (e.g. you-must-not-use-header-x-in-message-y) when we write our specs, and later use-cases come up where those restrictions cause problems. Backward compability is important, but forward compability is also important :) As far as other SDOs are concerned, at least 3GPP doesn't specify that a UA inserts 199 in Require. Regards, Christer > -----Original Message----- > From: Hadriel Kaplan [mailto:[EMAIL PROTECTED] > Sent: 24. marraskuuta 2008 7:37 > To: Dean Willis > Cc: Christer Holmberg; SIP IETF > Subject: RE: [Sip] Sip-199-02: majors and nits from Robert > > > > > -----Original Message----- > > From: Dean Willis [mailto:[EMAIL PROTECTED] > > Sent: Sunday, November 23, 2008 11:17 PM > > > > I'm not at all sure we can justify MUST NOT here. > > And that in a nutshell is why middleboxes end up doing > interop fixing stuff. > > > > It's not required for > > interop, does not cause harm to the network, > > There are thousands of deployed SIP networks. Not one of > them currently supports this 199 mechanism, AFAIK. Putting > it in a Require will not interoperate with any of them, and > has a potential for causing harm to the service SIP is > supposed to provide: session establishment. Obviously this > interoperates in the sense that the far-end will fail it, and > we have to be able to add option tags in Require for some new > things; but this 199 mechanism isn't in the same vein as > privacy or replaces option tags which need to be put in > Require sometimes to make calls work. Honestly we should > have been more careful in the past about this, so we might as > well start now. > > You may think this is a no-brainer, and that no one would be > so dumb as to put it in a Require, but history has already > proven otherwise for other option tags. Been there, done > that, have the T-shirt. It works in the closed environment > they deploy in at first, and then breaks when the environment > grows or is no longer closed. I can already envision what > will happen with 199: some other SDO will decide this 199 > thing is a good idea and makes the user experience better, so > it should be required in release X of their specs. > > > > and there are presumably > > legit use cases (such as diagnostics) for using it in a Require. > > Then say MUST NOT except for diagnostic purposes. > > -hadriel > _______________________________________________ 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
