From owner-freebsd-net@FreeBSD.ORG Fri Jan 30 14:00:13 2004 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id B15C216A4CE for ; Fri, 30 Jan 2004 14:00:13 -0800 (PST) Received: from mx2.nersc.gov (mx2.nersc.gov [128.55.6.22]) by mx1.FreeBSD.org (Postfix) with ESMTP id 3DB7943D1D for ; Fri, 30 Jan 2004 14:00:11 -0800 (PST) (envelope-from dart@nersc.gov) Received: by mx2.nersc.gov (Postfix, from userid 4002) id 55A8077A2; Fri, 30 Jan 2004 14:00:10 -0800 (PST) Received: from mx2.nersc.gov (localhost [127.0.0.1]) by localhost.nersc.gov (Postfix) with ESMTP id 76A17775D; Fri, 30 Jan 2004 14:00:01 -0800 (PST) Received: from gemini.nersc.gov (gemini.nersc.gov [128.55.16.111]) by mx2.nersc.gov (Postfix) with ESMTP id A2D22774A; Fri, 30 Jan 2004 14:00:00 -0800 (PST) Received: from gemini.nersc.gov (localhost [127.0.0.1]) by gemini.nersc.gov (Postfix) with ESMTP id 81179F8EB; Fri, 30 Jan 2004 14:00:00 -0800 (PST) X-Mailer: exmh version 2.6.3 04/04/2003 with nmh-1.0.4 To: Mike Hunter In-Reply-To: Message from Mike Hunter <20040130213935.GB25194@ack.Berkeley.EDU> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="==_Exmh_-966797664P"; micalg=pgp-sha1; protocol="application/pgp-signature" Content-Transfer-Encoding: 7bit Date: Fri, 30 Jan 2004 14:00:00 -0800 From: Eli Dart Message-Id: <20040130220000.81179F8EB@gemini.nersc.gov> X-Spam-Level: X-Spam-Checker-Version: SpamAssassin 2.60 (1.212-2003-09-23-exp) on mx2.nersc.gov X-Spam-Status: No, hits=-4.4 required=5.0 tests=AWL,BAYES_00 autolearn=ham version=2.60 cc: freebsd-net@freebsd.org Subject: Re: Assymetric results from iperf across gigabit link (long) X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 30 Jan 2004 22:00:13 -0000 --==_Exmh_-966797664P Content-Type: text/plain; charset=us-ascii In reply to Mike Hunter : > On Jan 30, "To freebsd-net@freebsd.org" wrote: > > > Hi, > > [snip] > > I switched the two pieces of hardware, and the photons still prefer going > uphill, so maybe there's a problem with the fiber after all. I'd still > appreciate any hints on what to ask freebsd to help me figure it out. > (Yes, we have real fiber test gear, this is more of an experiment.) Have you looked at interface error counts? (netstat -inbd) If you have dirty fiber, you could just be missing/corrupting the odd packet here and there, which would be enough to impact a high-bandwidth TCP flow. the other thing to check is if a UDP cannon has the same bandwidth asymmetry, since the UDP iperf tests don't have TCP's timidity (if memory serves me).... --eli > > Thanks, > > Mike > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" > --==_Exmh_-966797664P Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.3 (FreeBSD) Comment: Exmh version 2.5 07/13/2001 iD8DBQFAGtPgLTFEeF+CsrMRAq2sAJ9uFiOjntj/guvuzA21Cfjn7j9y4gCgwB/d kPdNA34Mhgy2Z1+lv9QCg1w= =u9Kc -----END PGP SIGNATURE----- --==_Exmh_-966797664P--