Re: AltQ + ng_iface

From: Chuck Swiger (cswiger_at_mac.com)
Date: 07/29/05

  • Next message: Daniel O'Connor: "Re: AltQ + ng_iface" 
    Date: Thu, 28 Jul 2005 21:32:21 -0400
To: Daniel O'Connor <doconnor@gsoft.com.au>

    Daniel O'Connor wrote:
    > On Friday 29 July 2005 10:10, Julian Elischer wrote:
    [ ... ]
    >>ipfw and dummynet work on ng_iface I believe.
    >
    > Well yeah, but dummynet is a little inflexible and can't prioritise ACKs (for
    > example)

    Either the "established" or the "tcpflags !syn,ack" keywords in a rule adding
    matching packets to a high-priority queue ought to do it...? Or perhaps you
    meant something more specific than just "TCP packets with TH_ACK" set? :-)

    Anyway, I'm not convinced that trying to classify packets within an established
    TCP connection in order to place them on different queues is a really good
    idea, since you're quite likely to reorder the packets by doing so. I'd expect
    both latency and bandwidth of a TCP connection to suffer very noticably if more
    than 10% or so of the packets arrive out of order...

    [ Hmm. I suppose that one could make an exception to the above generalization
    if URG was set, but the TCP stack already makes an effort to prioritize and
    deliver out-of-band urgent stuff as quickly as possible, anyway, right? ] 

    -- 
-Chuck
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  • Next message: Daniel O'Connor: "Re: AltQ + ng_iface"

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