From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: UDP path MTU discovery Date: Tue, 30 Mar 2010 18:06:02 +0200 Message-ID: <20100330160602.GS20695@one.firstfloor.org> References: <4BB0DCF6.9020401@hp.com> <20100329201431.GH20695@one.firstfloor.org> <20100329205035.GA32656@laped.iglesias.mooo.com> <4BB11510.9000302@hp.com> <1269898152.1958.86.camel@edumazet-laptop> <20100330052044.GJ20695@one.firstfloor.org> <20100330061627.GA22436@laped.iglesias.mooo.com> <20100330061952.GO20695@one.firstfloor.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andi Kleen , "Edgar E. Iglesias" , Eric Dumazet , Rick Jones , Glen Turner , "netdev@vger.kernel.org" To: "Templin, Fred L" Return-path: Received: from one.firstfloor.org ([213.235.205.2]:55845 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754079Ab0C3QGH (ORCPT ); Tue, 30 Mar 2010 12:06:07 -0400 Content-Disposition: inline In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: > Right again. Unlike IPv4, however, IPv6 does not allow > in-the-network fragmentation. So when in doubt, apps > that need to send isolated packets that may violate the > path MTU should really perform host-based fragmentation > with a maximum fragment size of 1280. Isn't there a > socket option "IPV6_USE_MIN_MTU" that apps can use to > force fragmentation on large packets (RFC3542)? Thanks for the pointer. The option is right now only defined, but not implemented. But yes it would help. -Andi -- ak@linux.intel.com -- Speaking for myself only.