Re: The TCP and UDP checksum algorithm may soon need updating

John Levine <johnl@taugh.com> Wed, 10 June 2020 01:08 UTC

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Subject: Re: The TCP and UDP checksum algorithm may soon need updating
Organization: Taughannock Networks
References: <D55AFBFD-0D59-4176-B6BD-D6A1801FEC2C@akamai.com> <6c9f5bd9-6e26-5d25-e66e-bec206473ff3@mtcc.com> <20200610001225.GD3100@localhost> <3ac60a21-4aee-d742-bedc-5be3a4e65471@mtcc.com>
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Cleverness: some
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In article <3ac60a21-4aee-d742-bedc-5be3a4e65471@mtcc.com>om>,
Michael Thomas  <mike@mtcc.com> wrote:
>So the long and short of this entire issue seems to be is, is the 
>uncaught error rate serious enough that warrant rethinking weak 
>transport and frankly L2 layer error detection? ...

Having read the papers that Craig referenced, that's my interpretation.

One of them is about a big physics application which sends multiple
terabytes of data over the net using what looks like a version of
FTP that transfers several files at once.  They send the data as a lot
of of 4 gig files. When they started verifying file checksums, they
found about 20% of the received files were corrrupted in transit.

In that application they resend the corrupt files and they obviously
need make the files smaller. But retransmitting a file at a time seems
a lot less efficient than improving the checksums and using the
existing TCP packet level retransmission.

-- 
Regards,
John Levine, johnl@taugh.com, Primary Perpetrator of "The Internet for Dummies",
Please consider the environment before reading this e-mail. https://jl.ly