Cheng, We run this in production at Limelight Networks (i.e toward a broad spectrum of Internet hosts) and must to deal with some uncommon network topology. There are currently some limitations as you point out.
Like you say the signaling is not perfect and we do often clamp MSS unnecessarily. There is also no probing to see if we can expand the MSS later. I think those issues should be fixed up before it's enabled by default and I don't know anyone working on it at the moment. Regards, On Wed, Mar 7, 2018 at 8:35 AM, Cui, Cheng <cheng....@netapp.com> wrote: > Dear all, > > Reading through the tcp blackhole detection code (support RFC 4821) in > FreeBSD including the recent bug fixes, I am wondering why is it still not > enabled in default? Given the fact that this implementation was a merge from > xnu, and the xnu has enabled it in default, do we have a plan to enable it in > default? Or is there any concern about the side-effect from it as performance > regression against some false positive blackhole event like a temporary link > flap, which is long enough to trigger a lower MSS but shorter than 6 RTO? > > https://opensource.apple.com/source/xnu/xnu-1456.1.26/bsd/netinet/tcp_timer.c.auto.html > << enabled in macOS 10.6 > https://reviews.freebsd.org/rS322967 << bug fixes > https://reviews.freebsd.org/rS272720 << merge from xnu > > Thanks, > --Cheng Cui > NetApp Scale Out Networking > https://netapp-meeting.webex.com/meet/chengc > > > _______________________________________________ > freebsd-net@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org" _______________________________________________ freebsd-net@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
