Re: Effective bandwidth reduction over WAN

From: David Cress (dcress_at_web.turner.com)
Date: 08/04/05

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    Date: Thu, 04 Aug 2005 14:59:01 -0400
To: Jeff Rosowski <rosowskij@ie.ymp.gov>

    This address will calculate a receive window size for you:
       www.speedguide.net/bdp.php

    and here are some good TCP tuning instructions, for Solaris:
       www.sean.de/Solaris/soltune.html#rexmit

    Jeff Rosowski wrote:
    > -----BEGIN PGP SIGNED MESSAGE-----
    > Hash: SHA1
    >
    >>> The results were
    >>>
    >>> 0 latency FTP – Ave. 39.5 mbps SCP – Ave. 39.4 mbps SFTP –
    >>> Ave. 38.8 mbps
    >>>
    >>> 60 millisec FTP – Ave. 37.7 mbps SCP – Ave. 2.9 mbps SFTP –
    >>> Ave. 2.9 mbps
    >>>
    >>> 100 millisec FTP – Ave. 33.0 mbps SCP – Ave. 2.0 mbps SFTP –
    >>> Ave. 1.8 mbps
    >>>
    >>> Can anyone tell me why the throughput of SCP and SFTP drop so
    >>> drastically when we try to use SSP protocols over a WAN?
    >
    >
    > Your problem is TCP itself. You can tweak your tcp window sizes, to let
    > you have more packets in flight. You could also use something that
    > would open multiple tcp connections for a single transfer.
    > -----BEGIN PGP SIGNATURE-----
    > Version: GnuPG v1.2.6 (FreeBSD)
    > Comment: For info see http://quantumlab.net/pine_privacy_guard/
    >
    > iD8DBQFC8kqrTs2s3OoD6D8RApi6AJkBzj2W/Kza9EjgdRR72ga1W4iDZQCeMPVm
    > myv7gwfj39smgaAji0tluw0=
    > =YKCu
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    -- 
David Cress
Lead Engineer
CNN Internet Technologies
http://www.cnn.com
--------------------
(404) 878-1921
What exists, exists; what is, is.
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