Re: JINETD and Other NICs - Hewlett Packard

This is a discussion on Re: JINETD and Other NICs - Hewlett Packard ; --- On Tue, 9/23/08, James Hofmeister wrote: We always recommended against cross over cables. Watch your link statistics and if you see problems, be prepared to install a switch between those 2 system's. ************************************************** ****** James, I have heard this ...

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Thread: Re: JINETD and Other NICs

  1. Re: JINETD and Other NICs

    --- On Tue, 9/23/08, James Hofmeister wrote:

    We always recommended against cross over cables.

    Watch your link statistics and if you see problems, be prepared to install a
    switch between those 2 system's.

    ************************************************** ******

    James,

    I have heard this recommendation several times, but I have never heard a reason why.

    I have installed cross over cables in specific situations, usually when shadowing with netbase to an HP3000 or SQL data warehouse.

    I have yet have any issues, (issues defined as problems seen in LINKCONTROL @,a).

    Why is it that HP recommends putting a switch in the middle?

    -Craig



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  2. Re: JINETD and Other NICs

    Craig Lalley wrote:
    > I have heard this recommendation several times, but I have never heard a reason why.
    > I have installed cross over cables in specific situations, usually when shadowing with netbase to an HP3000 or SQL data warehouse.
    > I have yet have any issues, (issues defined as problems seen in LINKCONTROL @,a).
    > Why is it that HP recommends putting a switch in the middle?


    A store-and-forward switch gives you a little buffer, as well as
    stabilize your interface to effects of your crossover-cabled neighbor.
    I'm not familiar with what sort of events would toggle the link on a
    3000 -- obviously power cycling, probably rebooting, don't know about
    resetting an interface -- but the 3000 does not react well to losing
    it's link. For a real network connection with any traffic, you'll get a
    gateway down condition, which the 3000 does not recover from
    automatically. For your crossover case, you may have no reason to reach
    the gateway and this may not be an issue. I don't know how long the
    3000 will tolerate the link down before generating a hard error.

    In general, providing a switch in the middle prevents link issues on one
    side from propagating to the other :-)

    Jeff

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  3. Re: JINETD and Other NICs

    From Jeff:
    > ... For a real network connection with any traffic,
    > you'll get a gateway down condition, which the 3000 does
    > not recover from automatically. For your crossover case,
    > you may have no reason to reach the gateway
    > and this may not be an issue. I don't know how long the
    > 3000 will tolerate the link down before generating a hard error.


    That is correct, there is no gateway configured.
    Is it therefore not a real network connection?
    (So it can report neither up nor down?)

    Netbase is the only software using this NI.
    (I presume Netbase is handling all the handshaking
    as a single purpose link.)

    Tracy Johnson
    Business Analyst
    Measurement Specialties, Inc.
    1000 Lucas Way
    Hampton, VA 23666
    Office 1-757-766-4318
    tracy.johnson@meas-spec.com
    www.meas-spec.com


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