[Asterisk-Users] a few questions about sip implementation

[Stephen Davies]

> >1. 8.2.6.1 Sending a Provisional Response says that UASs SHOULD NOT issue
> >a provisional response to non-INVITE requests.
> >
> >>From my message yesterday * appears to be sending a SIP/2.0 100 Trying to
> >X-Lite's REGISTER request before sending the SIP/2.0 200 OK message.
> >
> >Is this correct?
> 
> Yes, that is what it is doing and and while it may not adherent to 
> the exact reading of the RFC, I have seen several other proxies doing 
> the same thing (examples: FWD's SIP proxy (Cisco?) does send "100 
> Trying" but SER does not) so I will assume it's an awkward industry 
> standard, though perhaps not exactly compliant to the RFC paragraph 
> that you describe.

But note that SHOULD NOT != MUST NOT.

I assume this has been added as a clarification since the old
RFC.  They couldn't make it MUST NOT because of existing
implementations that already did it.

What I'm trying to say is that Asterisk doesn't fail compliance on
that point (though no doubt there are places where it does!)

Steve