Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 15 Feb 2001 15:54:53 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 15 Feb 2001 15:54:44 -0500 Received: from foobar.napster.com ([64.124.41.10]:25867 "EHLO foobar.napster.com") by vger.kernel.org with ESMTP id ; Thu, 15 Feb 2001 15:54:36 -0500 Message-ID: <3A8C4202.83C197D6@napster.com> Date: Thu, 15 Feb 2001 12:54:26 -0800 From: Jordan Mendelson Organization: Napster, Inc. X-Mailer: Mozilla 4.76 [en] (X11; U; Linux 2.4.0 i686) X-Accept-Language: en MIME-Version: 1.0 To: Rick Jones CC: kuznet@ms2.inr.ac.ru, roger@kea.GRace.CRi.NZ, linux-kernel@vger.kernel.org Subject: Re: MTU and 2.4.x kernel In-Reply-To: <200102151821.VAA19711@ms2.inr.ac.ru> <3A8C3EB5.BAB148B0@cup.hp.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Rick Jones wrote: > > > Default of 536 is sadistic (and apaprently will be changed eventually > > to stop tears of poor people whose providers not only supply them > > with bogus mtu values sort of 552 or even 296, but also jailed them > > to some proxy or masquearding domain), but it is still right: IP > > with mtu lower 576 is not full functional. > > I thought that the specs said that 576 was the "minimum maximum" > reassemblable IP datagram size and not a minimum MTU. RFC 1191 (Path MTU Discovery as it happens): Plateau MTU Comments Reference ------ --- -------- --------- 65535 Official maximum MTU RFC 791 65535 Hyperchannel RFC 1044 65535 32000 Just in case 17914 16Mb IBM Token Ring ref. [6] 17914 8166 IEEE 802.4 RFC 1042 8166 4464 IEEE 802.5 (4Mb max) RFC 1042 4352 FDDI (Revised) RFC 1188 4352 (1%) 2048 Wideband Network RFC 907 2002 IEEE 802.5 (4Mb recommended) RFC 1042 2002 (2%) 1536 Exp. Ethernet Nets RFC 895 1500 Ethernet Networks RFC 894 1500 Point-to-Point (default) RFC 1134 1492 IEEE 802.3 RFC 1042 1492 (3%) 1006 SLIP RFC 1055 1006 ARPANET BBN 1822 1006 576 X.25 Networks RFC 877 544 DEC IP Portal ref. [10] 512 NETBIOS RFC 1088 508 IEEE 802/Source-Rt Bridge RFC 1042 508 ARCNET RFC 1051 508 (13%) 296 Point-to-Point (low delay) RFC 1144 296 68 Official minimum MTU RFC 791 Jordan - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/