Auto negotiation or Full Speed - Connectivity

This is a discussion on Auto negotiation or Full Speed - Connectivity ; Hi there, I have a basic question about Auto Negotiation in a switch-server enviroment. Does Auto-Negotiation between a Nic and a Switch-Port has an impact on Network performance? What is the adviceable setup? Both the server and switch is capable ...

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Thread: Auto negotiation or Full Speed

  1. Auto negotiation or Full Speed

    Hi there,

    I have a basic question about Auto Negotiation in a switch-server
    enviroment. Does Auto-Negotiation between a Nic and a Switch-Port has an
    impact on Network performance?
    What is the adviceable setup? Both the server and switch is capable of a
    static 1000Mbit/Full setup. So could anybody give me a statement about pro
    and cons concerning Autonegotiation?

    Thank you!

    Andy



  2. Re: Auto negotiation or Full Speed

    Full speed setting on a NIC has always produced the best performance in my
    experience.
    I have supported Exchange clients that were having intermittent issues like
    calendar appointments dissappering from shared calendars. An adjustment to
    full 100Mbs speed on the workstation NIC improved performance.

    "Andreas Heinzelmann" wrote in message
    news:fpmcua$ro7$1@news.albasani.net...
    > Hi there,
    >
    > I have a basic question about Auto Negotiation in a switch-server
    > enviroment. Does Auto-Negotiation between a Nic and a Switch-Port has an
    > impact on Network performance?
    > What is the adviceable setup? Both the server and switch is capable of a
    > static 1000Mbit/Full setup. So could anybody give me a statement about pro
    > and cons concerning Autonegotiation?
    >
    > Thank you!
    >
    > Andy
    >




  3. Re: Auto negotiation or Full Speed

    On Fri, 22 Feb 2008 12:50:33 +0100, Andreas Heinzelmann wrote in
    alt.comp.networking.connectivity:

    >Hi there,
    >
    >I have a basic question about Auto Negotiation in a switch-server
    >enviroment. Does Auto-Negotiation between a Nic and a Switch-Port has an
    >impact on Network performance?
    >What is the adviceable setup? Both the server and switch is capable of a
    >static 1000Mbit/Full setup. So could anybody give me a statement about pro
    >and cons concerning Autonegotiation?


    Leave both devices to negotiate. Speed negotiation has been successfully
    implemented in network devices for a long time; duplex negotiation can
    be a problem. If transfer of substantial amounts of data is very slow,
    set both devices explicitly to full-duplex, or, if they don't support
    that, to half-duplex. The worst case is when one device is full-duplex
    and not capable of duplex-negotiation - that will put the negotiating
    device into half-duplex mode and leave the non-negotiating in
    full-duplex: duplex-mismatch. This will deliver speeds well below
    half-duplex performance.

    Whether full duplex will noticeably improve speed depends on a lot of
    things like cable lengths, amount of traffic, number of nodes, packet
    length. Full-duplex will (almost) never double the speed because traffic
    is (almost) never symmetrical in both directions. In my experience,
    half-duplex gives sometimes better performance.

    If all devices conform to 1000BASE-T, auto-negotiation everywhere will
    be fine.

    --
    Michael Bednarek http://mbednarek.com/ "POST NO BILLS"

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