Dieter> > 000016 IP bsd.63743 > src.65001: . ack 52 win 65535 Dieter> > 000011 IP bsd.63743 > src.65001: . ack 53 win 112 <------ why does Dieter> > the window suddenly shrink?
Chuck> I'd guess because both sides have requested that the connection Chuck> close That's probably the case. It just looked odd for the window size to suddenly shrink. Dieter> > The ack time is normally 12 or 13 microseconds, which seems to be Dieter> > okay. Dieter> > But 99.5 milliseconds is *way* too slow, data will be lost. Dieter> > Dieter> > Is TCP sitting around waiting for a second packet, so that Dieter> > it can be "efficient" and ack two packets at once? Chuck> Yup. Coalescing data before sending it results in less overhead. Dieter> > What can I do to fix this? Is there a knob I can turn to say Dieter> > "ack every packet", or "only wait xxx microseconds for a 2nd packet" ? Chuck> You can turn on TCP_NODELAY via setsockopt() to disable the Nagle Chuck> algorithm. There are probably sysctl's you can tweak, also... Bill> sysctl -d net.inet.tcp.delayed_ack Bill> net.inet.tcp.delayed_ack: Delay ACK to try and piggyback it onto a data packet Bill> Bill> That sysctl will turn it off for all network connections on the system. You Bill> can also set it on a per-socket basis using setsockopt and the TCP_NODELAY Bill> option. Some google searches on TCP_NODELAY will provide interesting Bill> technical details. That fixed one source of evil latency. Thanks! _______________________________________________ email@example.com mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"