Hi,
Actually no. I have been focusing on TCP over wireless with respect
to
the congestion control mechanism.
> -----Original Message-----
> From: Cannara [SMTP:cannara@ibm.net]
> Sent: Tuesday, December 15, 1998 10:30 PM
> To: Qaddoura, Emad [RICH2:IP10-M:EXCH]
> Cc: pilc
> Subject: Re: TCP over wireless type links
>
> Emad,
>
> Are you planning to simulate variants of transports other than those based
> on
> TCP?
>
> Alex
>
> -------------------
> Dr. A. B. Cannara
> Network Consulting Services
> Menlo Park, Ca.
>
>
> Emad Qaddoura wrote:
> >
> > In reference to
> > "It is probably hopeless to try and adapt TCP in a way
> > that it handles all of these vastly different link
> characteristics
> > optimally
> > at the same time (this does of course not prohibit certain
> > optimizations
> > which are beneficial for specific link types but don't decrease
> > performance
> > for others)."
> >
> > So, this make me think that, more than one TCP may have to exist.
> >
> > > -----Original Message-----
> > > From: Stephan Baucke [SMTP:stephan.baucke@eed.ericsson.se]
> > > Sent: Tuesday, December 15, 1998 5:23 AM
> > > To: pilc
> > > Subject: RE: TCP over wireless type links
> > >
> > > > It would also be hard to imagine that many link layers will
> adapt to
> > > > TCP requirements. It would
> > > > seem more of a managable problem to have TCP adapt to different
> link
> > > > behaviors. Therefore, the
> > > > suggestion below to have the document include the link layer
> > > > characteristics of various communication
> > > > links is a very good one.
> > >
> > > TCP is an end-to-end protocol, designed to run over paths which can
> > > comprise
> > > several vastly different links at the same time (e.g. it is very well
> > > possible to have a "long thin" wireless access link, "short fat"
> wireline
> > > networks and a "long fat" satellite link in the path your TCP/IP
> packets
> > > are
> > > travelling along). It is probably hopeless to try and adapt TCP in a
> way
> > > that it handles all of these vastly different link characteristics
> > > optimally
> > > at the same time (this does of course not prohibit certain
> optimizations
> > > which are beneficial for specific link types but don't decrease
> > > performance
> > > for others).
> > >
> > > Assuming this is true, two basic approaches are left: Either you split
> up
> > > your TCP connection and optimize TCP on each segment of the path
> > > individually (split-connection, spoofing, performance-enhancing
> proxies or
> > > whatever you call it), or you adapt each individual link so that it
> > > fulfills
> > > the assumptions made by TCP. The latter approach seems more sensible
> to
> > > me.
> > > Of course there are certain "hard" characteristics of wireless links
> which
> > > cannot be overcome by any protocol, but there are usually some degrees
> of
> > > freedom for the designers of link and physical layers (e.g. tradeoff
> > > between
> > > FEC and ARQ, channel coding vs. delay etc.).
> > >
> > > Stephan Baucke
> > > Ericsson Research
> > >
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