Date: Sat, 23 Jan 2016 09:15:36 -0800 From: Kevin Oberman <rkoberman@gmail.com> To: =?UTF-8?Q?Dag=2DErling_Sm=C3=B8rgrav?= <des@des.no> Cc: Julian Elischer <julian@freebsd.org>, FreeBSD Current <freebsd-current@freebsd.org>, FreeBSD-STABLE Mailing List <freebsd-stable@freebsd.org>, freebsd-security@freebsd.org Subject: Re: HPN and None options in OpenSSH Message-ID: <CAN6yY1vXFFsvfaZ4cHrnG9rzDee44tf=Dm4Qpaa4zOgG%2B-LUMg@mail.gmail.com> In-Reply-To: <861t98e1el.fsf@desk.des.no> References: <86mvrxvg79.fsf@desk.des.no> <56A2DE54.6070603@freebsd.org> <861t98e1el.fsf@desk.des.no>
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On Sat, Jan 23, 2016 at 7:55 AM, Dag-Erling Sm=C3=B8rgrav <des@des.no> wrot= e: > Julian Elischer <julian@freebsd.org> writes: > > what is the internal window size in the new ssh? > > 64 kB. > > DES > -- > Dag-Erling Sm=C3=B8rgrav - des@des.no Are you sure of this? I have not looked at the code, but my former colleagues at the high performance research network ESnet claim at http://fasterdata.es.net/data-transfer-tools/say-no-to-scp/ that the internal buffers and effective window size have recently been increased from 64KB to 1MB an allow for transfer rates of up to 140 Mbps over a link with 53 ms. latency. With the HPN patches, they report 1.2 Gbps, making HPN patches still significant over high latency paths. That said, scp still performed poorly when compared to other technologies (i.e. GridFTP) for bulk data transfer over high-latency high-bandwidth links. (ESnet provides links of up to 400 Gbps between the US and Europe as well as within the US, so this sort of thing is quite important to them.) -- Kevin Oberman, Part time kid herder and retired Network Engineer E-mail: rkoberman@gmail.com PGP Fingerprint: D03FB98AFA78E3B78C1694B318AB39EF1B055683
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