NIC dropping packets - HP UX

This is a discussion on NIC dropping packets - HP UX ; Hi to all, HP-UX 11.23, Itanium RX4640. NIC is dropping packets when pinging clients on the local LAN segment. Reboot solved the problem, but what can it be? (no firewalls between, no router, local segment) Logs show no defects. Speed ...

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Thread: NIC dropping packets

  1. NIC dropping packets

    Hi to all,

    HP-UX 11.23, Itanium RX4640. NIC is dropping packets when pinging clients on
    the local LAN segment.
    Reboot solved the problem, but what can it be? (no firewalls between, no
    router, local segment)

    Logs show no defects. Speed 100Mbit/full duplex as well as port on switch.

    Thx



  2. Re: NIC dropping packets

    ivica wrote:
    > HP-UX 11.23, Itanium RX4640. NIC is dropping packets when pinging
    > clients on the local LAN segment. Reboot solved the problem, but
    > what can it be? (no firewalls between, no router, local segment)


    Do you mean that ping reports dropped requests, or have you actually
    run lanadmin and seen drops in the link-level statistics? Can you
    provide us with the link-level stats?

    How about stats from the switch? And the destination system?

    > Logs show no defects. Speed 100Mbit/full duplex as well as port on
    > switch.


    Please say you aren't hardcoding NIC duplex settings.

    rick jones

    How 100Base-T Autoneg is supposed to work:

    When both sides of the link are set to autoneg, they will "negotiate"
    the duplex setting and select full-duplex if both sides can do
    full-duplex.

    If one side is hardcoded and not using autoneg, the autoneg process
    will "fail" and the side trying to autoneg is required by spec to use
    half-duplex mode.

    If one side is using half-duplex, and the other is using full-duplex,
    sorrow and woe is the usual result.

    So, the following table shows what will happen given various settings
    on each side:

    Auto Half Full

    Auto Happiness Lucky Sorrow

    Half Lucky Happiness Sorrow

    Full Sorrow Sorrow Happiness

    Happiness means that there is a good shot of everything going well.
    Lucky means that things will likely go well, but not because you did
    anything correctly Sorrow means that there _will_ be a duplex
    mis-match.

    When there is a duplex mismatch, on the side running half-duplex you
    will see various errors and probably a number of _LATE_ collisions
    ("normal" collisions don't count here). On the side running
    full-duplex you will see things like FCS errors. Note that those
    errors are not necessarily conclusive, they are simply indicators.

    Further, it is important to keep in mind that a "clean" ping (or the
    like - eg "linkloop" or default netperf TCP_RR) test result is
    inconclusive here - a duplex mismatch causes lost traffic _only_ when
    both sides of the link try to speak at the same time. A typical ping
    test, being synchronous, one at a time request/response, never tries
    to have both sides talking at the same time.

    Finally, when/if you migrate to 1000Base-T, everything has to be set
    to auto-neg anyway.

    --
    The computing industry isn't as much a game of "Follow The Leader" as
    it is one of "Ring Around the Rosy" or perhaps "Duck Duck Goose."
    - Rick Jones
    these opinions are mine, all mine; HP might not want them anyway...
    feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...

  3. Re: NIC dropping packets

    I havent't tried lanadmin at all :-(
    lanscan i ioscan revealed not much, I wasnt aware of lanadmin.

    Is there a way to get more info about dropped packets with this command?

    And, no, I haven't hardcoded duplex setting, I simply observer autnegotiated
    parameters while running at the production time...Switch port is auto
    negotiate.

    Best regards,

    Ivica

    "Rick Jones" wrote in message
    news:euyog.2328$ZW3.857@news.cpqcorp.net...
    > ivica wrote:
    >> HP-UX 11.23, Itanium RX4640. NIC is dropping packets when pinging
    >> clients on the local LAN segment. Reboot solved the problem, but
    >> what can it be? (no firewalls between, no router, local segment)

    >
    > Do you mean that ping reports dropped requests, or have you actually
    > run lanadmin and seen drops in the link-level statistics? Can you
    > provide us with the link-level stats?
    >
    > How about stats from the switch? And the destination system?
    >
    >> Logs show no defects. Speed 100Mbit/full duplex as well as port on
    >> switch.

    >
    > Please say you aren't hardcoding NIC duplex settings.
    >
    > rick jones
    >

    email to rick.jones2 in hp.com but NOT BOTH...



  4. Re: NIC dropping packets

    ivica wrote:
    > I havent't tried lanadmin at all :-(
    > lanscan i ioscan revealed not much, I wasnt aware of lanadmin.


    > Is there a way to get more info about dropped packets with this
    > command?


    What do you mean by more info? Beyond what you see, that is it. Can
    you post your lanadmin stats?

    > And, no, I haven't hardcoded duplex setting, I simply observer
    > autnegotiated parameters while running at the production
    > time...Switch port is auto negotiate.


    Out of curiousity, if you have not run lanadmin, how do you know the
    speed and duplex setting of the NIC?

    rick jones
    --
    Wisdom Teeth are impacted, people are affected by the effects of events.
    these opinions are mine, all mine; HP might not want them anyway...
    feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...

  5. Re: NIC dropping packets

    From switch side. If switch is set to autonegotiate and reports full duplex,
    100Mbit, it must be the same on the NIC, no? Otherwise would traffic
    suffering loss to all clients...

    > Out of curiousity, if you have not run lanadmin, how do you know the
    > speed and duplex setting of the NIC?
    >
    > rick jones
    > --
    > Wisdom Teeth are impacted, people are affected by the effects of events.
    > these opinions are mine, all mine; HP might not want them anyway...
    > feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...




  6. Re: NIC dropping packets

    ivica wrote:
    > From switch side. If switch is set to autonegotiate and reports full
    > duplex, 100Mbit, it must be the same on the NIC, no?


    A wise old engineer once tried to teach me the "proper" spelling was
    ass-u-me. Now, I've not always heeded that advice, but I think it
    would be a good idea to make an explicit check of the NIC via
    lanamdin.

    rick jones
    --
    portable adj, code that compiles under more than one compiler
    these opinions are mine, all mine; HP might not want them anyway...
    feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...

  7. Re: NIC dropping packets

    thx, wise advice, no doubt...That lanadmin.

    Best regards

    Ivica

    "Rick Jones" wrote in message
    news:%KTog.7$cL4.3@news.cpqcorp.net...
    > ivica wrote:
    >> From switch side. If switch is set to autonegotiate and reports full
    >> duplex, 100Mbit, it must be the same on the NIC, no?

    >
    > A wise old engineer once tried to teach me the "proper" spelling was
    > ass-u-me. Now, I've not always heeded that advice, but I think it
    > would be a good idea to make an explicit check of the NIC via
    > lanamdin.
    >
    > rick jones
    > --
    > portable adj, code that compiles under more than one compiler
    > these opinions are mine, all mine; HP might not want them anyway...
    > feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...




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