Attendees:  jtl@, rscheff@, tuexen@, thj@

====== Discussion ======
  * [[https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=252913|PR 252913]]: tuexen@ got a tracefile and some information from Netflix. This impacts stable/12. rrs@ will commit an update to RACK in main and MFC to stable/13. We don't plan to fix this bug in stable/12.
    * Actually, we probably should deprecate (and even remove) RACK code from stable/12. However, we do think we can maintain RACK code throughout stable/13 support cycle.
    * Will update tcp(4) and tcp_bbr(4) man pages, and write a new man page for RACK, to note whether stacks are experimental or supported.

  * [[https://reviews.freebsd.org/D23230|D23230]]: ECN++, rscheff@ updated the sysctl interface so sysctls are not checked in fast path. Needs review.

  * Lost retransmission detection: [[https://reviews.freebsd.org/D28931|D28931]] is an idea for doing SACK loss recovery in the base stack. (Documented in an [[https://datatracker.ietf.org/doc/draft-scheffenegger-tcpm-lrd/|I-D]].) Committed.

  * [[https://reviews.freebsd.org/D29441|D29441]], [[https://reviews.freebsd.org/D28822|D28822]]: PRR-related reviews still open. No plans to MFC D28822.

  * Follow up on the RST issue reported by NFS developer: We send a challenge ACK. Remote side sends a RST. We don't process the RST. rscheff@ proposed [[https://reviews.freebsd.org/D29690|D29690]]. This fixes the upcall problem, but we are unable to reproduce the problem where RSTs are rejected. rscheff@ will commit D29690 to fix the upcall problem.

===== New Items =====
  * We are more strict on timestamps. Some equipment negotiates timestamp support and never sends timestamps again. Apparently, at least one HP printer got a firmware upgrade this year and it now behaves in this way. tuexen@ will try to find someone at HP to notify them of the problem.

  * tuexen@ reports panic on ARM server in LRO and VNET. On vnet_restore(), the VNETs are 0.

  * tuexen@ reports a bug: send full-size frame in RACK, get packet-too-big message.
    * Netflix stack retransmits immediately and does not clear the PSH bit
    * %%FreeBSD%% stack retransmits 10ms later and does clear the PSH bit

  * Can we change our code so we panic less. (e.g. convert KASSERTS to new macros which cleanup on non-INVARIANTS kernels)

Next meeting: 03 April @ 1400 UTC