From owner-freebsd-net@FreeBSD.ORG Sat Dec 20 15:57:23 2003 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 75CD916A4CE for ; Sat, 20 Dec 2003 15:57:23 -0800 (PST) Received: from mail.sandvine.com (sandvine.com [199.243.201.138]) by mx1.FreeBSD.org (Postfix) with ESMTP id 9BF7C43D6A for ; Sat, 20 Dec 2003 15:57:14 -0800 (PST) (envelope-from don@sandvine.com) Received: by mail.sandvine.com with Internet Mail Service (5.5.2657.72) id ; Sat, 20 Dec 2003 18:57:12 -0500 Message-ID: From: Don Bowman To: 'Luigi Rizzo' , Alfred Perlstein Date: Sat, 20 Dec 2003 18:56:25 -0500 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2657.72) Content-Type: text/plain; charset="iso-8859-1" cc: net@freebsd.org Subject: RE: crossover between gigE? 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: Sat, 20 Dec 2003 23:57:23 -0000 From: Luigi Rizzo [mailto:rizzo@icir.org] > > On Sat, Dec 20, 2003 at 07:11:22AM -0800, Alfred Perlstein wrote: > > Any suggestion of the kind of cable one should look for at Frys > > to run between two gigE card (intel em0) to function as a crossover? > > A straight cable with all 4 pairs wired will work. GigE (and > many modern > 100Mbit switches) have auto polarity detection. > > cheers > luigi One caveat on that: if you force any of the phy parameters (e.g. speed, duplex), this defeats the auto polarity (MDI/MDX) detection on em, bge, and maybe others. ie to use the technique above you need to have autoselect enabled for duplex and speed. --don