Auto negotiation and Gigabit cards,

Archived from groups: comp.dcom.lans.ethernet (More info?)

I have a Gigabit card in a compaq server that is set to auto (negotiation
), Its connected to a port that is set to 100M Full Duplex, and yes I
realise that this is not a good idea.

The Gigabit card connects at 100M full duplex.

My understanding of the auto-negotiate process is that if one end has
fixed 100M and full duplex, the auto end will cease the normal auto
process pick up the 100M idle pulses and then switch to half-duplex.

So why does my server card switch to 100M full ?

Stuart.
14 answers Last reply
More about auto negotiation gigabit cards
  1. Archived from groups: comp.dcom.lans.ethernet (More info?)

    Stuartr@nospam.please (Stuart Robinson) wrote:
    >connected to a port that is set to 100M Full Duplex

    >The Gigabit card connects at 100M full duplex.

    >So why does my server card switch to 100M full ?

    What was the problem again?
  2. Archived from groups: comp.dcom.lans.ethernet (More info?)

    In article <o0gke190b2jvqfouoegkmji8jke33133fo@4ax.com>,
    <William P. N. Smith> wrote:
    :Stuartr@nospam.please (Stuart Robinson) wrote:
    :>connected to a port that is set to 100M Full Duplex

    :>The Gigabit card connects at 100M full duplex.

    :>So why does my server card switch to 100M full ?

    :What was the problem again?

    Stuart is expecting the negotation to fail to detect that the
    remote end is Full Duplex, and is wondering how, when the remote
    end is [supposedly] not sending any configuration pulses, that
    the local end is able to figure out the duplex anyhow.

    --
    Look out, there are llamas!
  3. Archived from groups: comp.dcom.lans.ethernet (More info?)

    Stuart Robinson <Stuartr@nospam.please> wrote:
    > I have a Gigabit card in a compaq server that is set to auto
    > (negotiation ), Its connected to a port that is set to 100M Full
    > Duplex, and yes I realise that this is not a good idea.

    Are you _quite_ sure that the GbE NIC is strapped to auto?

    > The Gigabit card connects at 100M full duplex.

    > My understanding of the auto-negotiate process is that if one end
    > has fixed 100M and full duplex, the auto end will cease the normal
    > auto process pick up the 100M idle pulses and then switch to
    > half-duplex.

    That is my understanding as well. I suppose GbE autoneg may have been
    "extended" in some way but still...

    > So why does my server card switch to 100M full ?

    Luck perhaps? It does not sound like a situation upon which one
    should rely.

    rick jones
    --
    denial, anger, bargaining, depression, acceptance, rebirth...
    where do you want to be today?
    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...
  4. Archived from groups: comp.dcom.lans.ethernet (More info?)

    Some devices will continue to send out autonegiation FLPs even if the port
    is configured with a fixed speed and duplex. It will just advertise only
    those fixed settings.


    "Rick Jones" <rick.jones2@hp.com> wrote in message
    news:tPuGe.9576$ro.4653@news.cpqcorp.net...
    > Stuart Robinson <Stuartr@nospam.please> wrote:
    >> I have a Gigabit card in a compaq server that is set to auto
    >> (negotiation ), Its connected to a port that is set to 100M Full
    >> Duplex, and yes I realise that this is not a good idea.
    >
    > Are you _quite_ sure that the GbE NIC is strapped to auto?
    >
    >> The Gigabit card connects at 100M full duplex.
    >
    >> My understanding of the auto-negotiate process is that if one end
    >> has fixed 100M and full duplex, the auto end will cease the normal
    >> auto process pick up the 100M idle pulses and then switch to
    >> half-duplex.
    >
    > That is my understanding as well. I suppose GbE autoneg may have been
    > "extended" in some way but still...
    >
    >> So why does my server card switch to 100M full ?
    >
    > Luck perhaps? It does not sound like a situation upon which one
    > should rely.
    >
    > rick jones
    > --
    > denial, anger, bargaining, depression, acceptance, rebirth...
    > where do you want to be today?
    > 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. Archived from groups: comp.dcom.lans.ethernet (More info?)

    > Are you _quite_ sure that the GbE NIC is strapped to auto?

    Yes, its a defined by a load line on a Netware server autoexec.ncf,
    although I suppose the driver could have a bug and is ignoring the auto
    command.

    > > So why does my server card switch to 100M full ?
    >
    > Luck perhaps? It does not sound like a situation upon which one
    > should rely.
    > So why does my server card switch to 100M full ?

    My thoughts too, I guess the person who decided that the card should be on
    auto tried it, found it worked and assumed it was therefore correct.


    Stuart.
  6. Archived from groups: comp.dcom.lans.ethernet (More info?)

    > Some devices will continue to send out autonegiation FLPs even if the
    > port is configured with a fixed speed and duplex. It will just
    > advertise only those fixed settings.

    Really ?

    That is interesting and would explain why it goes to 100Full, the switch
    in question is one of the Cisco Catalyst jobs.

    Is this part of the standard and do some manufacturers do it 'just in
    case'.

    Stuart.
  7. Archived from groups: comp.dcom.lans.ethernet (More info?)

    > What was the problem again?

    As Walter said, why does the card decide on FULL duplex ?

    Stuart.
  8. Archived from groups: comp.dcom.lans.ethernet (More info?)

    I believe that the 2950 will do this. I can't remember if its considered a
    bug or a feature. I did a quick search of the cisco web site but couldn't
    find anything one way or the other.

    "Stuart Robinson" <Stuartr@nospam.please> wrote in message
    news:memo.20050730083251.3568C@srnet.compulink.co.uk...
    >> Some devices will continue to send out autonegiation FLPs even if the
    >> port is configured with a fixed speed and duplex. It will just
    >> advertise only those fixed settings.
    >
    > Really ?
    >
    > That is interesting and would explain why it goes to 100Full, the switch
    > in question is one of the Cisco Catalyst jobs.
    >
    > Is this part of the standard and do some manufacturers do it 'just in
    > case'.
    >
    > Stuart.
  9. Archived from groups: comp.dcom.lans.ethernet (More info?)

    In article <trKGe.104049$oK.5221@okepread02>,
    "Noah Davids" <ndav1@cox.net> wrote:

    > I believe that the 2950 will do this. I can't remember if its considered a
    > bug or a feature. I did a quick search of the cisco web site but couldn't
    > find anything one way or the other.
    >

    This is perfectly acceptable behavior. It is neither required, nor
    prohibited by the standards, however, it is the *preferred* method of
    limiting device configuration in that it allows the type of scenario you
    describe (negotiating to 100 Mb/s FDX with a 10/100/1000 card).

    By the way, it should NOT be possible to disable Auto-Negotiation for a
    1000BASE-T-capable interface. A-N is used in 1000BASE-T for much more
    than determining speed and duplexity; various other operational
    parameters are negotiated, including selection of the clock master for
    the link. A-N is not optional for 1000BASE-T.

    > "Stuart Robinson" <Stuartr@nospam.please> wrote in message
    > news:memo.20050730083251.3568C@srnet.compulink.co.uk...
    > >> Some devices will continue to send out autonegiation FLPs even if the
    > >> port is configured with a fixed speed and duplex. It will just
    > >> advertise only those fixed settings.
    > >
    > > Really ?
    > >
    > > That is interesting and would explain why it goes to 100Full, the switch
    > > in question is one of the Cisco Catalyst jobs.
    > >
    > > Is this part of the standard and do some manufacturers do it 'just in
    > > case'.
    > >


    --
    Rich Seifert Networks and Communications Consulting
    21885 Bear Creek Way
    (408) 395-5700 Los Gatos, CA 95033
    (408) 228-0803 FAX

    Send replies to: usenet at richseifert dot com
  10. Archived from groups: comp.dcom.lans.ethernet (More info?)

    > By the way, it should NOT be possible to disable Auto-Negotiation for a
    > 1000BASE-T-capable interface. A-N is used in 1000BASE-T for much more
    > than determining speed and duplexity; various other operational
    > parameters are negotiated, including selection of the clock master for
    > the link. A-N is not optional for 1000BASE-T.

    I understand that there is only Auto for the 1000BASE-T side, but are you
    saying it should not be possible (via a driver setting) to fix a a 1000
    BASE-T capable card to 100Mfull, 100Mhalf etc ?

    Stuart.
  11. Archived from groups: comp.dcom.lans.ethernet (More info?)

    In article <memo.20050731081821.2688A@srnet.compulink.co.uk>,
    Stuartr@nospam.please (Stuart Robinson) wrote:

    > > By the way, it should NOT be possible to disable Auto-Negotiation for a
    > > 1000BASE-T-capable interface. A-N is used in 1000BASE-T for much more
    > > than determining speed and duplexity; various other operational
    > > parameters are negotiated, including selection of the clock master for
    > > the link. A-N is not optional for 1000BASE-T.
    >
    > I understand that there is only Auto for the 1000BASE-T side, but are you
    > saying it should not be possible (via a driver setting) to fix a a 1000
    > BASE-T capable card to 100Mfull, 100Mhalf etc ?
    >

    Of course, you may be able to configure a 1000BASE-T capable card to not
    use that capability, either by advertising only lower capabilities, or
    by a fixed configuration at 10 or 100 Mb/s. What it is NOT possible to
    do is to create a fixed (i.e., non-negotiated) 1000BASE-T configuration,
    since negotiation is required to achieve such operation.


    --
    Rich Seifert Networks and Communications Consulting
    21885 Bear Creek Way
    (408) 395-5700 Los Gatos, CA 95033
    (408) 228-0803 FAX

    Send replies to: usenet at richseifert dot com
  12. Archived from groups: comp.dcom.lans.ethernet (More info?)

    Rich Seifert wrote:
    > In article <memo.20050731081821.2688A@srnet.compulink.co.uk>,
    > Stuartr@nospam.please (Stuart Robinson) wrote:
    >
    >
    >>>By the way, it should NOT be possible to disable Auto-Negotiation for a
    >>>1000BASE-T-capable interface. A-N is used in 1000BASE-T for much more
    >>>than determining speed and duplexity; various other operational
    >>>parameters are negotiated, including selection of the clock master for
    >>>the link. A-N is not optional for 1000BASE-T.
    >>
    >>I understand that there is only Auto for the 1000BASE-T side, but are you
    >>saying it should not be possible (via a driver setting) to fix a a 1000
    >>BASE-T capable card to 100Mfull, 100Mhalf etc ?
    >>
    >
    >
    > Of course, you may be able to configure a 1000BASE-T capable card to not
    > use that capability, either by advertising only lower capabilities, or
    > by a fixed configuration at 10 or 100 Mb/s. What it is NOT possible to
    > do is to create a fixed (i.e., non-negotiated) 1000BASE-T configuration,
    > since negotiation is required to achieve such operation.
    >
    >
    > --
    > Rich Seifert Networks and Communications Consulting
    > 21885 Bear Creek Way
    > (408) 395-5700 Los Gatos, CA 95033
    > (408) 228-0803 FAX
    >
    > Send replies to: usenet at richseifert dot com

    IOW if one ONLY wants to see 10BASET protocol from a 10/100/100BASET
    capable interface the PHY must only advertise 10BASET? Same with 100BASET?

    Thanks in advance.
  13. Archived from groups: comp.dcom.lans.ethernet (More info?)

    In article <6Q5He.22$fJ1.14@newssvr13.news.prodigy.com>,
    JoeG <JoeG@none.com> wrote:

    >
    > IOW if one ONLY wants to see 10BASET protocol from a 10/100/100BASET
    > capable interface the PHY must only advertise 10BASET? Same with 100BASET?
    >

    The PHY can either advertise that capability (using Auto-Negotiation),
    or forgo Auto-Negotiation altogether and just apply the desired
    10/100BASE-T signaling. An Auto-Negotiating device at the other end of
    the link will parallel detect the signaling and configure itself to that
    mode of operation (assuming that it is capable of doing so).


    --
    Rich Seifert Networks and Communications Consulting
    21885 Bear Creek Way
    (408) 395-5700 Los Gatos, CA 95033
    (408) 228-0803 FAX

    Send replies to: usenet at richseifert dot com
  14. Archived from groups: comp.dcom.lans.ethernet (More info?)

    Rich Seifert wrote:
    > In article <memo.20050731081821.2688A@srnet.compulink.co.uk>,
    > Stuartr@nospam.please (Stuart Robinson) wrote:
    >
    >
    >>>By the way, it should NOT be possible to disable Auto-Negotiation for a
    >>>1000BASE-T-capable interface. A-N is used in 1000BASE-T for much more
    >>>than determining speed and duplexity; various other operational
    >>>parameters are negotiated, including selection of the clock master for
    >>>the link. A-N is not optional for 1000BASE-T.
    >>
    >>I understand that there is only Auto for the 1000BASE-T side, but are you
    >>saying it should not be possible (via a driver setting) to fix a a 1000
    >>BASE-T capable card to 100Mfull, 100Mhalf etc ?
    >>
    >
    >
    > Of course, you may be able to configure a 1000BASE-T capable card to not
    > use that capability, either by advertising only lower capabilities, or
    > by a fixed configuration at 10 or 100 Mb/s. What it is NOT possible to
    > do is to create a fixed (i.e., non-negotiated) 1000BASE-T configuration,
    > since negotiation is required to achieve such operation.
    >

    Nice try... We have encountered some older Broadcom chip sets plus
    Cisco 2930 who do require a bit of fig'in to get 1000Base-T
    configuration to work by the use of Manual Configuration.

    A bloody pain here for while (until the next HW rev.)
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