From owner-freebsd-hackers Wed Mar 25 10:34:26 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id KAA03472 for freebsd-hackers-outgoing; Wed, 25 Mar 1998 10:34:26 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from terra.Sarnoff.COM (terra.sarnoff.com [130.33.11.203]) by hub.freebsd.org (8.8.8/8.8.8) with SMTP id KAA03391 for ; Wed, 25 Mar 1998 10:34:11 -0800 (PST) (envelope-from rminnich@Sarnoff.COM) Received: (from rminnich@localhost) by terra.Sarnoff.COM (8.6.12/8.6.12) id NAA09816; Wed, 25 Mar 1998 13:33:42 -0500 Date: Wed, 25 Mar 1998 13:33:42 -0500 (EST) From: "Ron G. Minnich" X-Sender: rminnich@terra To: freebsd-hackers@FreeBSD.ORG Subject: Re: ARP REQUEST question In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Wed, 25 Mar 1998, David E. Cross wrote: > I see what you are saying with corrupted packets being introduced by a > flaky ethernet card, but keep in mind that true 'end to end' detection and > reliability is not possible, if you have a bad memory circut, in the place > wher you are building the packet in the kernel, you are going to get a Don't forget, it's not just on your machine. It's on any device (router or switch) between your memory and the destination computer's memory. That covers a lot of ground. > It is also of note how laughable the Internet checksums are, they are 16 > bit modulo 2^16 checksums, they are NOT CRCs... a simple byte swap can yes, in fact you have just brought to mind one of the very few advantages that ATM has over both Ethernet and IP checksums: ATM AAL5 has a CRC-32 (as good as ethernet, much better than IP) that is end-to-end (as good as IP, much better than Ethernet). There's only a few places where ATM is a winner, and this is one of them. ron To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message