Re: Last Call: Security Architecture for the Internet Protocol to Proposed Standard

From: Francesco Potorti` ([email protected])
Date: Wed Apr 01 1998 - 04:39:08 EST


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Christian Huitema wrote:

   By the way, it should be noted that the only rationale, if any, for
   TCP spoofing in the satellite relays is the inadequacy of the
   end-to-end TCP implementation. The specificities of satellites and
   their interaction with transport protocols have been known for more
   than 15 years, and the cure is also very well known: use large
   windows, use selective acknowledgments.

Correct me if I'm wrong. Using big windows is good if you know your
path includes a satellite (or big pipe) link. It is not necessarily
good in general. In particular, if the receiving host is behind a
slow line (say, a modem at home), the only effect of advertising a big
window is to build a big queue at the router where the slow line
connects to, with a consequent series of bad effects on throughout as
soon as the queue overflows and packets are dropped.

If what I said is true, the problem is not inadequacy of the TCP
implementation, but it is more complex.

-- 
Francesco Potorti` (researcher)        Voice:    +39-50-593 203 (op. 211)
Computer Networks Group                Fax:      +39-50-904052
CNUCE-CNR, Via Santa Maria 36          Email:    [email protected]
56126 Pisa - Italy                     Web:	 http://fly.cnuce.cnr.it/



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