25Jan2018 [FreeBSD WIKI]

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====== Hangout 25 Jan 2018 ======

  * Reviewed minutes of [[TransportProtocols/11Jan2018|last meeting]]

  * tuexen@ discussed a quirk of the way the current %%FreeBSD%% TCP-FO server implementation works: accept() does not return until the three-way handshake completes or the server gets data in the SYN/ACK. This defeats TCP-FO's benefit for protocols (e.g. SSH) where the server sends the first byte. Should accept return right away, even if there is no data? tuexen@ will write to pkelsey@.

  * jegg reports a case where cwnd is set to 0 (or apparently underflows) in some custom code. However, he also found a problem in cubic. It is computing the cwnd as a 64-bit value, then assigning it to a 32-bit value. So, for very large values of cwnd, it essentially assigns random values to cwnd. jegg will develop a patch to enforce a max of INT32_MAX. jegg will also audit the 64-bit calculations to see if they are correct.