Re: Using DNS for SSM

[Toerless Eckert <eckert@cisco.com>]

Can someone explain to me what the urgent need for SSM specific
channel addresses is ? I agree that it is a nice-to-have,
but such a mapping alone does not allow a user who wants
to receive a channel to simply type the address and then receive
the content.

In the first place, i think the question is: What is a simple
to remember URL scheme that is sufficient as a root pointer for
a receiver application to automatically get all the session
information needed to receive content. With just an S and a G
the application doesn't really stand much of a chance. 

In the web, a FQDN alone is sufficient, because everybody
makes the assumption that the access-scheme is HTTP. What
is the assumption you would want to make in the streaming media
case ? I wouldn't know one. I think the best way to actually
solve this issue is to think about some simplification for
mappings from URLs onto SDP files, because the SDP file is
the only standardised and accepted way to transimit sufficient
information (S,G,port,protocol, etc) for a receiver application
to be able to receive content. I don't see why in the process
of finding a simplified FQDN->URL->SDP mappings you would need
to come up with new RR types or even with some new DNS schemes
to encode a channel.

Now i see a need for DNS encoding of Channels, but just in
the reverse direction: If you're running a network and see
(S,G) state, you'd probably like to get to the SDP file also
to learn about the characteristics of the content. But again,
just doing a (S,G)->FQDN mapping doesn't seem to get us 
much further towards FQDN->SDP.

Just my 2cents on this.

Toerless