Re: int-serv over e.g. ATM

[Steve Deering <[e-mail]>]

Mark,

> ...The only way to get productive, I think, is to go through a bit of
> identifying the obvious.

Good.  I was worried that you might take offence at me stating the obvious
(at least, what I hoped was the obvious).

> For example, one of the logical conclusions [of the pure IP model] is
> that ATM is just another subnet du jour. ...  While ATM *can* be
> deployed that way, it is also expected to be deployed in ways that
> will challenge the subnet model.  Imagine ATM LANs connected to ATM
> public networks with ATM over satellite to the All-Europe ATM cloud,
> with connections to the proper Internet at multiple points.  As a
> subnet, it's not pretty.

It's not especially uglier than any other VC-oriented, large-cloud
technology, like X.25 or ISDN.

>  Maybe we can ignore this aspect of ATM, or maybe some small but elegant
> feature in the routing tables will make it all work right, but I'm not
> prepared to call it a non-problem.

What's your idea of "working right"?  Why should the Internet architecture
be changed to accommodate ATM, when we didn't feel compelled to change it
to accommodate X.25 or ISDN?  What's so special about ATM that should
cause us to treat it as anything *other* than just another subnet du jour?

> Again, I probably don't have the best vocabulary handy for this, but I
> would recommend a distinction between the piece of the "IP layer" that
> slaps a header on the data and forwards it through the network, and
> the function in the router (or elsewhere) that receives an RSVP
> message and translates it appropriately into control messages (i.e.
> other than encapsulated user data) for the next subnet.  OK (reading
> another message), you're calling this "the subnet interface".  Still,
> the name doesn't strongly distinguish between "in the data path" and not.

I agree with your distinction.  In my previous message, I used the phrase
"the module that processes RSVP", as an attempt to avoid layer connotations.
Does that help?

Steve