nanog mailing list archives

Re: Best utilizing fat long pipes and large file transfer


From: "Kevin Oberman" <oberman () es net>
Date: Thu, 12 Jun 2008 19:11:06 -0700

Date: Fri, 13 Jun 2008 09:02:31 +0900
From: Randy Bush <randy () psg com>

The idea is to use tuned proxies that are close to the source and
destination and are optimized for the delay. Local systems can move data
through them without dealing with the need to tune for the
delay-bandwidth product. Note that this "man in the middle" may not
play well with many security controls which deliberately try to prevent
it, so you still may need some adjustments.

and for those of us who are addicted to simple rsync, or whatever over
ssh, you should be aware of the really bad openssh windowing issue.

Actually, OpenSSH has a number of issues that restrict performance. Read
about them at <http://www.psc.edu/networking/projects/hpn-ssh/>

Pittsburgh Supercomputer Center fixed these problems and on FreeBSD, you
can get these by replacing the base OpenSSH with the openssh-portable
port and select the HPN (High Performance Networking) and OVERWRITE_BASE
options. I assume other OSes can deal with this or you can get the
patches directly from:
<http://www.psc.edu/networking/projects/hpn-ssh/openssh-5.0p1-hpn13v3.diff.gz>

The port may also be built to support SmartCards which we require for
authentication. 
-- 
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman () es net                       Phone: +1 510 486-8634
Key fingerprint:059B 2DDF 031C 9BA3 14A4  EADA 927D EBB3 987B 3751

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