RE: Collision on NIC

From: Sten Daniel Sørsdal (sten.daniel.sorsdal_at_wan.no)
Date: 05/30/03

  • Next message: Neelkanth Natu: "Alpine4Linux" 
    Date: Fri, 30 May 2003 18:59:18 +0200
To: "Erwane Breton" <breton@erwane.net>, <freebsd-net@freebsd.org>

    > > >
    > > > Well, I don't see the problem.
    > > >
    > > > My math says that that's .03% collision rate, which is so
    > deep in the
    > > > noise as to be practically zero. What do you _think_ it
    > should be?
    > > >
    > > Even Mr. Inventor of the ethernet himself regrets calling
    > them collisions because
    > > that term has a bad ring people unfamiliar with the
    > technological detail.
    > >
    > > Pete
    >
    > So there are no answers or solutions ?
    >
    > Erwan

    Answer:

    Collisions are normal when your ethernet interface is set to Half-duplex.
    In Half-duplex mode it can only either send or listen.

    Changing both sides to full-duplex removes to collisions.
    However: Changing only one side _always_ results in packet-loss!

    Collisions does not mean packets lost.

    10mbit Half-duplex from your computer to your ADSL modem does not mean
    loss of performance.

    The reason that your ADSL modem is at 10mbit Half-duplex is usually either;
            * It does not support anything else (almost always the case)
            * Auto-detect will in certain cases fail and there would be duplex mismatch
            (packetloss) requiring operators assistance.

    Either way, it is the way it is because then practically nothing can go wrong.

    Solution: Do absolutly nothing.

    You would (probably) have realized so many reasons not to ask this question if you
    had spent 10 seconds on www.google.com. And don't tell me you have, because you havent.

    - Sten
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