Hi All
I've had a question from a colleague in Australia facing an interesting
problem. Due to the high-expense of cable under the Pacific it appears that
one ISP is suggesting (or has in fact set it up) to put http downstream
traffic over a satellite link, nationally and internationally. This would
mean that requests go over terrestrial lines and responses come back over
satellite (to be reinjected onto terrestrial links locally).
http may not be the only traffic to face this modification, but it would
certainly be the highest impact. (ftp and email would cover a lot, then
there's the various multimedia streaming/realtime protocols, DNS, ICQ?, ...)
Besides the obvious impact of increased rtt's, or bandwidth*delay products,
(you can't go under the Pacific for less than 200ms rtt, or to geosynch and
back for much under 500ms) what other issues leap to mind, regarding tcp
performance on assymetric services and very-long/thin pipes? Malcolm asked
if there are any "classic" papers that cover this. I don't know of any
(although I'm looking at RFC2488 and its excellent references to start
with) but I see that the PILC charter has a couple of milestone documents
due about now:
May 99 Submit Internet-Draft on long-thin networks (based on
draft-montenegro-pilc-ltn-01.txt) submitted to the IESG for publication.
Jun 99 Draft on asymmetric network paths.
neither of which I can find online yet - so somebody here is presumably
working on this as I type :-)
[oh - just found the first one at
http://mirror.aarnet.edu.au/ietf/internet-drafts/draft-montenegro-pilc-ltn-0
2.txt - sorry]
>From Malcolm:
>[on Monday 6 Sep] we want to
>discuss issues of routing web traffic over satellite circuits. (It would
seem
>that currently XXXXXXXX is routing our http traffic over satellite,
perhaps in
>one direction only)
>
>I have a feeling that there are a few classic papers about the problems of
>using tcp over satellite circuits, and the disadvantages of running tcp over
>asymmetric paths.
Any help, comments, advice, references, brickbats or bouquets appreciated !
By Monday would be great :-), but any time thereafter too would be very
useful.
Thanks !
Cheers,
Markus
Markus Buchhorn, Advanced Computational Systems CRC | Ph: +61 2 62798810
email: [email protected], snail: ACSys, RSISE Bldg,|Fax: +61 2 62798602
Australian National University, Canberra 0200, Australia |Mobile: 0417 281429
This archive was generated by hypermail 2b29 : Mon Feb 14 2000 - 16:14:56 EST