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    SubjectRe: [PATCH] tcp: Implement a two-level initial RTO as per draft RFC 2988bis-02.
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    Am 19.05.2011 um 08:42 schrieb tsuna:

    > On Wed, May 18, 2011 at 11:36 PM, Alexander Zimmermann
    > <alexander.zimmermann@comsys.rwth-aachen.de> wrote:
    >> If you set the initRTO=0.1s, it's good for me but bad for the rest of the
    >> world. That's the difference.
    >>
    >> Or do you want to implement a lower barrier of 1sec so that you can ensure
    >> that nobody set the initRTO lower than 1s?
    >
    > Oh, I see. Yes, there is a lower bound (and an upper bound) on what
    > values the kernel will accept as initRTO. In the patch "Implement a
    > two-level initial RTO as per draft RFC 2988bis-02" above, I re-used
    > TCP_RTO_MIN and TCP_RTO_MAX in net/ipv4/sysctl_net_ipv4.c in order to
    > prevent users from setting a minRTO that's outside this range. They
    > are defined as follows in tcp.h:
    >
    > #define TCP_RTO_MAX ((unsigned)(120*HZ))
    > #define TCP_RTO_MIN ((unsigned)(HZ/5))
    >
    > So we're talking about a [200ms ; 120s] range no matter what.

    Why is 200ms a valid lower bound for initRTO? I'm aware of
    measurements that 1s is save for Internet, but I don't know of any
    studies that 200ms is save...

    >
    > --
    > Benoit "tsuna" Sigoure
    > Software Engineer @ www.StumbleUpon.com

    //
    // Dipl.-Inform. Alexander Zimmermann
    // Department of Computer Science, Informatik 4
    // RWTH Aachen University
    // Ahornstr. 55, 52056 Aachen, Germany
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