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Re: wanted: wireless magic tricks

  • From: Jon Mansey
  • Date: Thu Aug 16 14:14:26 2001

Then there are performance-enhancing proxies that terminate the TCP session, turn the data into UDP to send over sat, and then re-originate as TCP. This eliminates the adverse effects of bandwidth-delay over sat links.

See Mentat, FlashNetworks and Fourelle for PEPs.

This is of course doable over satellite, the problem probably is the "occasional-use" nature of the BW requirement, its likely to bump up the cost per Mb considerably over operating a full time connection.


 > Well, that is quite wonderful, but when I approached this problem
 with a collegue of mine over a sat link for a client that wasn't
 our experience and after considerable tweaking we ended up having
 to settle for less.

 PS: got pointers to documents detailing the 500mbps over OC-12 sat link?
     email addr will do, as well, I'd love to find out what they did.
Yep, sorry -- I should have included a pointer.  Try:

    David E. Brooks, Craig Buffinton, Dave R. Beering, Arun Welch,
    William D. Ivancic, Mike Zernic, Douglas J. Hoder. ACTS 118x
    Final Report High Speed TCP Interoperability Testing, July 1999.

In the first couple of pages they show a results of 473 Mbps over an
OC-12 circuit (a little less than line rate, but still quite good)
using Solaris.  Results with other operating systems varied.  I seem
to remember a presentation at the TCP Over Satellite IETF WG where
over 500 Mbps was reported.

My main point was that there is nothing wrong with the TCP
*protocol* that makes it under-perform at large delay*bandwidth
products.  The implementations are not necessarily up to the job in
some cases, but the protocol is sound.

(Further reference might be the TCPSAT WG's two RFCs: 2488 and 2760).


Mark Allman -- BBN/NASA GRC --

[email protected]                          Chief Science Officer
Verestar Networks, Inc.          
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