Re: [Sip] SIP backward compatibility issue

["Adam Roach" <adam@dynamicsoft.com>]

"Prakash R" <rprakash@cdotb.ernet.in> wrote in message
3E0C50C8.4060302@cdotb.ernet.in">news:3E0C50C8.4060302@cdotb.ernet.in...

> An rfc3261 stack compliant stack will be 100% backward compatible with a
> rfc2543 stack? I can just get the two stacks to interwork without any
> issues at all? All the rfc2543 gear already deployed will work smoothly
> with a new stack? Hope this is true... Makes life simple for us.

Yes, that was a design goal for RFC3261. That said, there are "holes" in
RFC2543 -- places in which the protocol was underspecified. Interop tests
and operational experience have revealed these holes; all the ones that we
have discovered to date have been fixed in RFC3261. So, there are ways to
implement an RFC2543 stack that won't work in general (even with other
RFC2543 stacks). There is obviously no magic fix for these problems.

> I was earlier thinking of using this branch-tag to check which rfc the
> remote stack was complying with. Was not clear with all the scenarios
> though.


Don't do that. Don't even try. You still encounter a huge number of stacks
that use the branch parameter but don't do 100% of RFC3261.

> BTW, When will the protocol version be incremented? What sort of changes
> will necessitate a protocol version upgrade?