Delayed ACK triggered by Header Prediction

Noritoshi Demizu demizu at
Wed Mar 16 05:30:57 PST 2005

Thank you very much for your reply.

Actually, I am using GbE on my DragonFlyBSD box.

Here is my experimental environment.

  Sender (FreeBSD Stable) --- Router (FreeBSD 5.3R) --- Receiver (DragonFlyBSD)

  (Bandwidth = 100Mbps, RTT = 100ms, router queue length = 64 pkts.
   On the router above, dummynet runs with HZ=1000.)

All ethernet interfaces above are Broadcom BCM5703 GbE.  So, there is
a possibility that receive interrupts for ACK segments are aggregated.

I think TCP performance reduction is due to bandwidth-delay product.
In my environment, if slow start grew slowly, the TCP performance
became poor.  I am sorry I did not describe my experimental environment.
I should do so.  It was important information in my story.

I have not experienced DragonFlyBSD on normal LAN.  I did not talk
about the performance on LAN.  I am sorry for my ambiguous report.

Today, I took many packet traces of my experiments.  But they have gone...
Tomorrow, I will take another traces and put onto my web page.

Thank you.

Noritoshi Demizu

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