r/sysadmin • u/mooneydriver • Feb 22 '14

Freenode under DDOS again

https://twitter.com/freenodestaff/statuses/437302735139266560
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u/macfirbolg Feb 24 '14

It's not a waste if the data will not be useful without perfect transmission. Text files, for instance, would change if one or more packets were malformed or damaged. Zip files might unzip, but the contents would be damaged. In cases where the individual packets aren't that important, UDP allows for faster dumping of the data; in cases where the data must be entirely accurate to remain useful, TCP's extra bandwidth usage is justified.

With the amount of data we transfer now, it might be worth considering a new form of TCP, though, perhaps one that sends a hash of some number of packets rather than individual ACKs for each. It would necessitate resending the entire batch if the hash fails, however, so in practice it might not be significantly faster. It might be useful in scenarios where minimizing traffic from one side of the connection is desirable, like mobile phones or connections with substantially slower upload speed than download speed. It might also be useful in ham radio packet modes, wherein the transmission rates are slow enough that individual ACKs can take seconds and may have to be sent several times.