From owner-freebsd-net@FreeBSD.ORG Thu Apr 17 17:28:32 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 2077537B401 for ; Thu, 17 Apr 2003 17:28:32 -0700 (PDT) Received: from pyroxene.sentex.ca (pyroxene.sentex.ca [199.212.134.18]) by mx1.FreeBSD.org (Postfix) with ESMTP id 30FB343F93 for ; Thu, 17 Apr 2003 17:28:31 -0700 (PDT) (envelope-from mike@sentex.net) Received: from simian.sentex.net (simeon.sentex.ca [192.168.43.27]) by pyroxene.sentex.ca (8.12.9/8.12.8) with ESMTP id h3I0SU8D091507; Thu, 17 Apr 2003 20:28:30 -0400 (EDT) (envelope-from mike@sentex.net) Message-Id: <5.2.0.9.0.20030417202920.07adb1e0@marble.sentex.ca> X-Sender: mdtpop@marble.sentex.ca (Unverified) X-Mailer: QUALCOMM Windows Eudora Version 5.2.0.9 Date: Thu, 17 Apr 2003 20:34:47 -0400 To: Brooks Davis From: Mike Tancsa In-Reply-To: <20030418001904.GA23983@Odin.AC.HMC.Edu> References: <16031.17219.159093.279782@canoe.velocet.net> <16031.17219.159093.279782@canoe.velocet.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed X-Virus-Scanned: By Sentex Communications (lava/20020517) cc: freebsd-net@freebsd.org Subject: Re: vlan0 on em0 has mtu 1496 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, 18 Apr 2003 00:28:32 -0000 At 05:19 PM 17/04/2003 -0700, Brooks Davis wrote: >On Thu, Apr 17, 2003 at 08:13:55PM -0400, David Gilbert wrote: > > Why does a vlan created against em0 have a mtu of 1496. > >Because the vlan header takes up 4 bytes. With em(4) devices it looks >like fixing that should be a simple matter of raising the real >interface's MTU to 1504. Why the difference in behavior vs how the fxp driver works with respect to vlans ? ---Mike