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Just how reliable is NFS?
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Mike Muuss
Sep 29, 1986, 1:27:06 PM9/29/86
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You seem to miss the point that the UDP checksum is an End-to-end
protection measure, while the Ethernet CRC is a link-level
protection measure. In a one-ethernet system, the UDP checksum only
protects you from bad interfaces or bad software. (By the way,
interface boards DO fail in such a way as to send in garbaged packets...
sometime get me to tell you about the board that mangled 50% of the
packets it sent. Nice thing was, neither TCP nor UDP were upset, because
they were protected by their checksums...)
protection measure, while the Ethernet CRC is a link-level
protection measure. In a one-ethernet system, the UDP checksum only
protects you from bad interfaces or bad software. (By the way,
interface boards DO fail in such a way as to send in garbaged packets...
sometime get me to tell you about the board that mangled 50% of the
packets it sent. Nice thing was, neither TCP nor UDP were upset, because
they were protected by their checksums...)
In a complicated network, such as the real InterNet, which at last count
had 150 networks operating connected together by scores of gateways,
end-to-end protection measures are *vital*, because you have no way
to know (or control) what technology is used to convey your packet.
Your error rates will vary.
-Mike Muuss
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