From owner-freebsd-questions Wed Oct 24 4:59:56 2001 Delivered-To: freebsd-questions@freebsd.org Received: from serenity.mcc.ac.uk (serenity.mcc.ac.uk [130.88.200.93]) by hub.freebsd.org (Postfix) with ESMTP id 013E837B401 for ; Wed, 24 Oct 2001 04:59:54 -0700 (PDT) Received: from dogma.freebsd-uk.eu.org ([130.88.200.97] helo=dogma) by serenity.mcc.ac.uk with esmtp (Exim 2.05 #6) id 15wMPc-000KSB-00; Wed, 24 Oct 2001 12:41:33 +0100 Received: (from jcm@localhost) by dogma (8.11.4/8.11.1) id f9OBfVX54739; Wed, 24 Oct 2001 12:41:31 +0100 (BST) (envelope-from jcm) Date: Wed, 24 Oct 2001 12:41:30 +0100 From: j mckitrick To: cjclark@alum.mit.edu Cc: freebsd-questions@FreeBSD.ORG Subject: Re: question about mtu and fragment offset Message-ID: <20011024124130.A54685@dogma.freebsd-uk.eu.org> References: <20011019134824.A9949@dogma.freebsd-uk.eu.org> <20011022225420.E364@blossom.cjclark.org> <20011024010617.A50480@dogma.freebsd-uk.eu.org> <20011023224232.B5743@blossom.cjclark.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0.1i In-Reply-To: <20011023224232.B5743@blossom.cjclark.org>; from cristjc@earthlink.net on Tue, Oct 23, 2001 at 10:42:32PM -0700 Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG | The offset field indicates where the data portion of the current | fragment datagram lies in the original "complete" datagram. | | Say we have a 5001 byte (20 bytes of header and 4981 bytes of data) | datagram that needs to cross a 1500 MTU network. The fragment datagram | will have a 20-byte header too, so we can put 1480 bytes of the data | in it. The next fragment will contain data that starts at that | 1480-byte offset from the start of the original datagram. The header | is _not_ included in offset calculation. The result will be something a-ha! This was the point of contention i had with my prof. Everyone seemed to think the offset included the header, but that didn't make sense to me. Thanks for the explanation. Fortunately, my project has one line that if taken out, changes the behavior to what apparently is correct. Thanks again. jm -- My other computer is your windows box. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message