From owner-freebsd-net Thu Dec 30 3: 2:55 1999 Delivered-To: freebsd-net@freebsd.org Received: from tango.SoftHome.net (tango.SoftHome.net [204.144.231.49]) by hub.freebsd.org (Postfix) with SMTP id 2A8CA152F1 for ; Thu, 30 Dec 1999 03:02:53 -0800 (PST) (envelope-from fgont@softhome.net) Received: (qmail 24143 invoked by uid 417); 30 Dec 1999 11:02:51 -0000 Received: from unknown (HELO over) (200.51.58.193) by smtpb.softhome.net with SMTP; 30 Dec 1999 11:02:51 -0000 Message-Id: <.19991229211419.009c8b10@pop.softhome.net> X-Sender: fgont@pop.softhome.net X-Mailer: QUALCOMM Windows Eudora Pro Version 4.2.0.58 Date: Wed, 29 Dec 1999 21:22:40 -0300 To: justin@apple.com From: Fernando Ariel Gont Subject: Re: Two many CRCs? Cc: freebsd-net@FreeBSD.ORG In-Reply-To: <199912290213.SAA01337@walker3.apple.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org At 18:13 28/12/1999 -0800, Justin C. Walker wrote: >Third, there's still a chance (cosmic rays, you know) that a packet >really might get munged after it is in host memory, but before the >stack layers have their look at it. This is possible, and has been >observed. It gets less likely over time. Ok, but... Was that taken as a *reason* for adding a CRC field? I mean, I can't understand that a CRC field was added because someone thought that the packets could get damaged in memory... If so, what about the OS code that is in memory???? >Forth, the protocol CRCs cover different portions of the packet. >For IP, it's *just* the IP header; for TCP, it's just the TCP >"packet" (plus the "pseudo header"). Ok, but.... why isn't there only one CRC field at the IP layer that covers the *whole* IP datagram? If it were like this, I think a CRC field at TCP or UDP would not be necessary... Best regards, Fernando Ariel Gont E-mail: fgont@softhome.net web site: http://members.xoom.com/gont/ --- "Con las computadoras crearemos una civilizacion de estupidos tecnologicos, y una elite se ira quedando con todo. Cuando digo elite me refiero a gente como yo, que puede leer." - Ray Bradbury, escritor To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message