[e2e] TCP smarm

[Joe Touch]

Jon Crowcroft wrote:
> In missive <200404261635.JAA07867 at gra.isi.edu>, Bob Braden typed:
> 
>  >>I would like to ask each of you to limit your contributions to the
>  >>current threads to a maximum of one message to the list per 24 hour
>  >>period, per thread.
>  
>  Bob,
> 
> ok - here's a new thread.
> 
> TCP encouters a lot of problems when confronted with random loss -
> packets in flight on wireless links have a higher chance of loss due
> to turbulance - little vortices in the ether are setup as the edges of
> the bits in the packet interfere. Its clear that there are several
> solutions that involve changing TCP, but I intend to experiment with a
> sub-IP solution, but still an end-to-end (or at least, wall-to-wall)
> solution.
> 
> What we need to do is to reduce the fuzziness aroudn the edge of
> wireless packets, so that they travel more smoothly through the ether
> - this calls for a balanced asynchronous encoding of packets,
> something we call Forward Edge Completion - it can be implemented in
> the link layer, or in IP, but it can also easily be done by a new TCP
> option, which encodes the payload differently - essentially we borrow
> the idea from NRZ(I) type frame encoding techniques -if you look
> closely at a typical TCP data packet, there are lots of 1s and 0s -
> the 1s interfere much more than 0s, so what we need to do is to
> runlength encode the values as 
> n 0s
> is the value n

Any encoding intended to affect the number of 1's or 0's on the wire had 
better operate at the link layer, not E2E. Various encodings munge the 
network layer packet to make trying to do so elsewhere useless, including:

	net level encryption (e.g., IPsec)
	link level encryption (e.g., WEP)
	physical layer encoding (e.g., 4B/5B)

The remainder of this point appears moot in this context, IMO.

Joe
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