From owner-freebsd-net@FreeBSD.ORG Thu Jan 29 08:40:14 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 0136D16A4CE; Thu, 29 Jan 2004 08:40:14 -0800 (PST) Received: from mx2.nersc.gov (mx2.nersc.gov [128.55.6.22]) by mx1.FreeBSD.org (Postfix) with ESMTP id 6D00F43D1F; Thu, 29 Jan 2004 08:40:05 -0800 (PST) (envelope-from dart@nersc.gov) Received: by mx2.nersc.gov (Postfix, from userid 4002) id 43D0A7752; Thu, 29 Jan 2004 08:40:05 -0800 (PST) Received: from mx2.nersc.gov (localhost [127.0.0.1]) by localhost.nersc.gov (Postfix) with ESMTP id B9F4A775B; Thu, 29 Jan 2004 08:40:01 -0800 (PST) Received: from gemini.nersc.gov (gemini.nersc.gov [128.55.16.111]) by mx2.nersc.gov (Postfix) with ESMTP id 730767752; Thu, 29 Jan 2004 08:40:01 -0800 (PST) Received: from gemini.nersc.gov (localhost [127.0.0.1]) by gemini.nersc.gov (Postfix) with ESMTP id 61DE5F8EB; Thu, 29 Jan 2004 08:40:01 -0800 (PST) X-Mailer: exmh version 2.6.3 04/04/2003 with nmh-1.0.4 To: Don Lewis In-Reply-To: Message from Don Lewis <200401290330.i0T3UP7E085602@gw.catspoiler.org> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="==_Exmh_-1058242534P"; micalg=pgp-sha1; protocol="application/pgp-signature" Content-Transfer-Encoding: 7bit Date: Thu, 29 Jan 2004 08:40:01 -0800 From: Eli Dart Message-Id: <20040129164001.61DE5F8EB@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=-4.3 required=5.0 tests=AWL,BAYES_00 autolearn=ham version=2.60 cc: net@FreeBSD.org Subject: Re: jumbo-frames on the network 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: Thu, 29 Jan 2004 16:40:14 -0000 --==_Exmh_-1058242534P Content-Type: text/plain; charset=us-ascii In reply to Don Lewis : > On 28 Jan, Garrett Wollman wrote: > > < > > >> Can different MTUs be mixed on the same wire > > > > No. > > It's ugly, but I wonder if adding host routes with the -lock -mtu > options might work ... I wouldn't even mess with it. If you have an MTU mismatch on the same layer-2 domain, you have a Broken Network. If you manage to make it work with duct tape and zip ties, you're only setting yourself up for operational pain down the road. Just put a layer-3 hop in between your standard frame and jumbo frame hosts, and you're good to go. The other thing people often do is block all ICMP because "ICMP is bad" and then wonder why path MTU discovery breaks :P --eli > _______________________________________________ > 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_-1058242534P Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.3 (FreeBSD) Comment: Exmh version 2.5 07/13/2001 iD8DBQFAGTdhLTFEeF+CsrMRApSGAJ9dRKgThcWy/2uAfXMjCq/iXMtXeACfQ1W2 JYlUZ8iNKYwOyt80kSNnhgA= =9SH1 -----END PGP SIGNATURE----- --==_Exmh_-1058242534P--