Date: Wed, 13 Jun 2001 23:11:13 -0700 From: Terry Lambert <tlambert2@mindspring.com> To: "Louis A. Mamakos" <louie@TransSys.COM> Cc: Mike Smith <msmith@FreeBSD.ORG>, Bsdguru@aol.com, freebsd-hackers@FreeBSD.ORG Subject: Re: How to disable software TCP checksumming? Message-ID: <3B285581.4CFBBEF3@mindspring.com> References: <200106092135.f59LZW701229@mass.dis.org> <200106110103.f5B13HI87819@whizzo.transsys.com>
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"Louis A. Mamakos" wrote: > > Setting aside the degree to which you choose to be paranoid about > where data can be corrupted, and the likelyhood thereof-- there > is an architectural issue here, which is that the CRC provided > by your friendly neighborhood Ethernet NIC card only protects the > data over one Ethernet subnetwork. The TCP checksum, and TCP in > general, provides end-to-end semantics, independent of the > concatenation of physical links the TCP segments might transit from > the source to the destination. If you have an end-to-end protocol, > with end-to-end semantics, then you need and end-to-end mechanism. I think you need to read the Tigon II driver in the /sys/pci directory, and come back when you realize that it supports offloading the TCP checksum. FWIW: The Intel Gigabit, Tigon III, and several other Gigabit cards support this, as well. -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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