From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 25 Jan 2001 21:24:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 25 Jan 2001 21:24:39 -0500 Received: from quattro.sventech.com ([205.252.248.110]:22797 "HELO quattro.sventech.com") by vger.kernel.org with SMTP id ; Thu, 25 Jan 2001 21:24:24 -0500 Date: Thu, 25 Jan 2001 21:24:20 -0500 From: Johannes Erdfelt To: "David S. Miller" Cc: "H. Peter Anvin" , linux-kernel@vger.kernel.org Subject: Re: hotmail not dealing with ECN Message-ID: <20010125212419.G20628@sventech.com> In-Reply-To: <94qcvm$9qp$1@cesium.transmeta.com> <14960.54069.369317.517425@pizda.ninka.net> <3A70D524.11362EFB@transmeta.com> <14960.54852.630103.360704@pizda.ninka.net> <3A70D7B2.F8C5F67C@transmeta.com> <14960.56461.296642.488513@pizda.ninka.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.95.4i In-Reply-To: <14960.56461.296642.488513@pizda.ninka.net>; from David S. Miller on Thu, Jan 25, 2001 at 06:10:21PM -0800 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 25, 2001, David S. Miller wrote: > > H. Peter Anvin writes: > > > RFC793, where is lists the unused flag bits as "reserved". > > > That is pretty clear to me. It just has to say that > > > they are reserved, and that is what it does. > > > > > > > Is the definition of "reserved" defined anywhere? In a lot of specs, > > "reserved" means MBZ. > > > > Note, that I'm not arguing with you. I'm trying to pick this apart. > > It says "reserved for future use, must be zero". > > I think the descrepency (and thus what the firewalls are doing) comes > from the ambiguous "must be zero". I cannot fathom the RFC authors > meaning this to be anything other than "must be set to zero by current > implementations" or else what is the purpose of the "reserved for > future use part" right? > > Honestly, is there anyone here who can tell me honestly that when they > see the words "reserved" in the description of a bit field description > (in a hardware programmers manual of some device, for example) that > they think it's ok the read the value and interpret it in any way? > > To me it's always meant "we want to do cool things in the future, > things we haven't thought of now, so don't interpret these bits so we > can do that and you will still work". Generally it's to ensure that all implementations set those bit by default to 0 as well. Then in the future, 0 means "I don't support this feature either by choice or by not implementing it yet". JE - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/