Date: Wed, 25 Mar 1998 11:11:34 -0800 From: David Greenman <dg@root.com> To: "Ron G. Minnich" <rminnich@Sarnoff.COM> Cc: freebsd-hackers@FreeBSD.ORG, pratap singh <v_pr@hotmail.com> Subject: Re: ARP REQUEST question Message-ID: <199803251911.LAA12206@implode.root.com> In-Reply-To: Your message of "Wed, 25 Mar 1998 09:04:16 EST." <Pine.SUN.3.91.980325090244.8488A-100000@terra>
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>On Tue, 24 Mar 1998, David Greenman wrote: >> > pratap singh wrote: >> >I have a basic doubt. Every layer has a cehcksum being calculated >> >whereas the ARP frame does not have. Can anyone throw light on this >> >please. Is it because the ARP packets donot traverse the LAN boundary >> >and error rates in LAN environment are very low compared to the WAN >> >error rates???? >> All ethernet packets have a 32bit CRC, so the arps are protected by that. > >until it hits the first switch or router. Past that point the arp can be >garbaged any way you please, and the damage is undetectable. It's not an >end-to-end checksum. Do arps cross gateways and switches? in some places, >yes. Switches should be checking the CRC on inbound packets and discarding them if it is bad, so I don't see a problem. -DG David Greenman Core-team/Principal Architect, The FreeBSD Project To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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