From owner-freebsd-firewire@FreeBSD.ORG Tue Aug 10 10:33:30 2004 Return-Path: Delivered-To: freebsd-firewire@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id EA41716A4CE for ; Tue, 10 Aug 2004 10:33:30 +0000 (GMT) Received: from bbnest.net (r135052.ap.plala.or.jp [220.108.135.52]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2C58643D1F for ; Tue, 10 Aug 2004 10:33:30 +0000 (GMT) (envelope-from bland@FreeBSD.org) Received: from [127.0.0.1] (bland@localhost [127.0.0.1]) by bbnest.net (8.13.1/8.13.1) with ESMTP id i7AAXGPG002136; Tue, 10 Aug 2004 19:33:17 +0900 (JST) (envelope-from bland@FreeBSD.org) Message-ID: <4118A46B.9030901@FreeBSD.org> Date: Tue, 10 Aug 2004 19:33:15 +0900 From: Alexander Nedotsukov User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.7.2) Gecko/20040810 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Doug Rabson References: <4116EA33.8040405@FreeBSD.org> <200408090859.34574.dfr@nlsystems.com> <411843FD.4090201@FreeBSD.org> <200408100851.32087.dfr@nlsystems.com> <41189199.5020201@FreeBSD.org> <1092133653.13089.0.camel@builder02.qubesoft.com> In-Reply-To: <1092133653.13089.0.camel@builder02.qubesoft.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit cc: freebsd-firewire@FreeBSD.org Subject: Re: max MTU for fwip device. X-BeenThere: freebsd-firewire@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Firewire support in FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 10 Aug 2004 10:33:31 -0000 >>>Interesting. The specification for IPv6 on firewire is clearer: >>> >>> The default MTU size for IPv6 packets on an IEEE1394 network is 1500 >>> octets. This size may be reduced by a Router Advertisement [DISC] >>> containing an MTU option which specifies a smaller MTU, or by manual >>> configuration of each node. If a Router Advertisement received on an >>> IEEE1394 interface has an MTU option specifying an MTU larger than >>> 1500, or larger than a manually configured value, that MTU option may >>> be logged to system management but MUST be otherwise ignored. The >>> mechanism to extend MTU size between particular two nodes is for >>> further study. >>> >>> >>> >>> >>Mmm. I still do not see any prohibition of MTU size > 1500. What I see >>here is definition of automatic MTU adjustment. It's stated that ATM MTU >>size may be only reduced by such mechanism. Am I right? >>So manual configuration of interface for MTU size > 1500 violates nothing. >> >> > >Of course - I certainly don't want to stop people from configuring an >MTU size > 1500. I just think that for the compiled in default, we >should go with the spec for now. > > > I do not object default MTU either. But the problem is we have hardcoded 1500 limit in SIOCSIFMTU ioctl handler ATM. Check sys/net/if_fwsubr.c ;-)