Switches made things slower

Discussion in 'Cisco' started by Trent Collicutt, Jan 19, 2004.

  1. I've seen that happen too. Sometimes they change their mind even
    without any negotiation and the result will be a duplex mismatch.

    But, the original description was that the error counters are clear.

    Therefore no mismatch can exist unless we have been mislead. ;)
    Mismatch shows up very quickly in counters as soon as there
    has been a good amount of load for some time.

    At no load it might work fine and the counters could be clear.
    So, at an unloaded moment a quick check might show nothing.
    Generating some load is a good idea when seaking those.
    Harri Suomalainen, Jan 22, 2004
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  2. A classic "ping-pong" protocol, with all the attendant extreme
    sensitivity to any delay.
    Not that I am aware of... unless you are currently running 100M end to
    end with hubs or cut-through switches only. But the delay introduced
    waiting for a 1500 byte packet at 100Mbps is only 120 microseconds.
    Hence the white paper is usually irrelevant once the slowest speed on
    the network is 100Mbps.
    Could be queueing delays (they start to become measureable at around
    30% of available bandwidth). More likely, you're hitting the PPS limit
    of the routing engine, at which point the queueing delays can become
    VERY significant.
    I always qualify that recommendation with the adjective "competent."
    I'll never forget the day 12 years ago I introduced myself at a
    professional society meeting as an independent consultant and the
    engineer next to me remarked "Yea, I just got laid off too..."
    Vincent C Jones, Jan 22, 2004
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  3. No, the counters were clear, and hadn't been cleared for some time
    either. The 5 min avg was about 1.5 meg with no errors. As soon as I
    changed the duplex to half, the throughput took off. With a 10 meg
    workstation feed, I was downloding at 8.5 Mbps without errors.

    Unless the counters weren't telling me what eas actually going on.
    Trent Collicutt, Jan 22, 2004
  4. Cool!!!!!

    Reminds me of the time I followed the instructions in the help files
    on a 1900 switch and made one of the 100 Meg ports a network port.
    Switch couldn't remember any MAC addresses for more than 5 minutes
    until I turned the feature off.

    It's like one of my instructors told me in school. "If this stuff was
    easy, noone would pay you to do it."
    Trent Collicutt, Jan 22, 2004
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