RE: Do we actually need dynamic ports?

[Melinda Shore <mshore@cisco.com>]

At 12:57 PM 3/28/02 -0500, Paul Koning wrote:
>There's FTP (though that has a workaround -- passive mode).  There's
>H.323, widely considered an amazingly ugly protocol.  Are there any
>others that matter?

Um, SIP, SRTP, ...

The reasons that H.323 are considered ugly have less to do
with dynamic port allocation than they do with overall system
design, which is basically a link-by-link replacement of
existing telephony signaling systems and the heavy use of
signaling mediation by a third party (gatekeeper).  

There are legitimate reasons to allocate media channels on the 
fly, including (but not limited to) allowing multiple 
simultaneous connections, allowing media with different traffic 
characteristics in the same call (you *really* don't want to 
multiplex audio and video on the same channel), allowing media 
with different security characteristics in the same call, 
allowing different media channels to be routed independently, 
allowing big hairy multiparty conferences without degrading audio 
quality, and so on.

>Is there "an increasing number" of these protocols?  Or do protocol
>designers realize that it's a bad idea to design protocols like this?

I hope not, because it's not a bad idea.

Melinda