P.S. How many folks out there have phones (hard or soft) from
which they can
place calls to other random SIP endpoints? (I do, but also realize
I'm in a minority.)
The only reason that the average corporate desktop phone can make long
distance calls to anywhere in the world is that their local PABX
supports routing those calls.
In the same way, any arbitrary SIP phone (hard or soft) can also make
calls to arbitrary SIP endpoints if they are connected to a SIP PABX
that supports routing the calls. See <http://www.asterisk.org> for the
leading open-source SIP PABX software.
Even if the IETF needs something that Asterisk can't do today, it would
be wise to implement it anyway so that Asterisk developers can see the
Ietf mailing list