Curtis and the tcp-sat group;
This is such a good example of the "latency gap" issue that I just had
to comment. Curtis is 100% right-on in describing what I hope is the goal of
our group. Knowing full well the complexity and variety of situations in which
our work may be applied, it is vital to identify the set of options to consider
when adapting TCP to a satellite link. Showing what does (or doesn't) work, and
the reasons some TCP defaults are "dumb" and why a "dumb" default in one
situation is "smart" in another is key information.
However, ... the AT&T comments are literally the real world "out there"
intruding on our little piece of cyberspace. Who do we convey to the layman
(management, press, etc. ...) that while there are technical issues, "all's
right with the world and the Internet"? We (technical folks) have to remember
that for all our good work, an active PR "hack" can create lots of "fear and
dread" with little or no effort. We should also consider vanquishing this enemy
as well.
.....victor
_______________________________________________________________________________
Subject: Re: Purpose of the Draft - Focus of the WG
From: [email protected] at CCGATE
Date: 12/9/97 9:30 PM
In message <[email protected]>, "Lynch
, Tom" writes:
> After careful review of the Draft "Enhancing TCP over Satellite Channels
> using Standard Mechanisms (v01)" we came to the conclusion that the
> document seems to lack a goal/focus. What are we trying to achieve?
> Now that we have identified the factors that limit performance in a
> satellite based network, and identified different approaches to mitigate
> some of these problems, will any specific recommendations be made to
> change the requirements to the TCP protocol? Are we going to suggest
> that some of the enhancements that are currently in most current
> releases (such as Fast Retransmit, Windows scaling) be upgraded to
> Required Status? Perhaps it is time to revisit the goals of the group.
> Otherwise this document runs the risk of being short lived and ignored.
>
>
> Thomas J Lynch
> AT&T Laboratories
> [email protected]
>
> Dr. Enrique G. Cuevas
> Satellite Communications
> International Network Technology Development
> AT&T Laboratories
> [email protected]
I'm not sure why the document would be ignored. In a nutshell it says
that there are some really stupid ways to use TCP some of which are
changeable defaults and some of which are built in to specific less
cluefull vendor implementations and there are smarter ways to use TCP
*as is*. Using TCP *as currently defined* but insuring that your
vendor supports certain RFCs (such as Path MTU Discovery, RFC1323 and
in particular window scaling, and SACK) and making sure these options
are enabled and some configuration done can make a few decimal orders
of magnitude difference in performance.
In considering this as an Informational RFC, this sort of thing
strikes me as *very* useful information. It describes the worst and
best that can be done using the existing standards. It is a useful
product of the WG though not nessecarily the only product of the WG.
Curtis
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