Re: Virtual Circuit protocols => universal access

Rick Troth (
Mon, 22 Aug 1994 20:13:08 +0200

> My argument was that virtual circuit technology is more widely
> deployed, presumably because it's easier to "tunnel" VC's inside each
> other than to encapsulate datagrams. I think the conclusion that VC's
> are more widely deployed holds (I believe the Merit statistics report
> that FTP, HTTP, and Gopher constitute over 50% of all packets on the
> internet), but I don't know if I have correctly identified the cause.

So basically, good or bad, VC is used more.

> To my mind, HTTP _is_ an RPC protocol:
> the client sends a request, and the server answers. That's why I think
> it's overkill to use TCP.

Saying "it's overkill to use TCP" really really scares me.
Maybe it's just because I'm familiar with TCP and not with RPC.
More likely it's because I see the elegance of a different paradigm:
streams, not functions. Functions are great, but when you try to
"portablize" them, they're not as great.

> Or by RPC do you mean Sun RCP with their stubgen and all that? Or
> would DCE RPC, or ILU RPC do the trick?

I'd think Sun RPC. have to read-up-on DCE again.

> Could you elaborate on the distinction between RPC and messaging?

Messaging is cool. How do you feel about messaging kernels?
I think they're great. But in a kernel (for example) you have a
much more reliable "transport". One could still lose "packets",
but it's not quite the given for a kernel that it is for IP.

If you want messaging to be "reliable" in/on IP, you have to
build something_like TCP on top of it. Maybe (probably!) what you
build will be more efficient (for the web) than TCP, but it completely
destroys the stream model. Not that you can't fashion some new and
more wonderful stream model, but I'll have to create or use completely
new tools. That's expensive.

> Dan

I say, go ahead and do it. But don't expect the rest of
the web to use it for a long time. If it really is mo betta,
as I honestly believe it can be, then we'll all come on over to
your camp as soon as it's stable.

Rick Troth <>, Rice University, Information Systems 
"Remember when we first were led to heaven's door 
by the hands of those who showed us something more? 
Their arms were open with no strings attached, 
and the words they spoke to us meant so much more." 
							-- Out of the Grey