No link between fiber converter and Catalyst 6500, works with Router 7301

Discussion in 'Cisco' started by Hoffa, Jan 12, 2007.

  1. Hoffa

    Hoffa Guest

    Greetings all

    I have tried to find an answer to and issue like this before but
    without success.
    I've tried for some day now to get a fiber connection between an
    IMCnetworks MM850 GigabitTP<->Fiber converter up and running. The fiber
    is on my end connected to a SX SPF. When I connect the cable and enable
    the interface I get a LinkUp light on the media converter but no link
    on my Cat6500. I've tried different autodetect, negotiation and speed
    settings but nothing works. I've also tried different SPFs and switched
    As a final solution I plugged the fiber cable into our 7301 router,
    bypassing our Cat6500. After I set the port to "no negotiate auto" the
    link went up on the 7301.

    How can the same cable and same SPF work on the 7301 but not on my
    Cat6500? Is there some setting I'm missing here?

    Fredrik Hofgren
    Hoffa, Jan 12, 2007
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  2. Hi Fredrik,

    When a user cannot get a Gigabit Ethernet link up between a Cisco
    switch and a non-Cisco device due to auto-negotiation incompatibility
    and the cable between the devices is known to be good and is the
    correct type, yet the link does not light up, one of these commands may
    need to be issued on the Cisco Gigabit interface:

    On a CatOS-based switch, the set port negotiation mod#/port# disable

    On a Cisco IOS-based switch, the no negotiation auto command.

    Be sure to disable auto-negotiation on the connected device as well.

    An alternative to disabling auto-negotiation is to contact the vendor
    for a software or hardware upgrades for IEEE 802.3z Gigabit
    auto-negotiation support.

    For more information, refer to the Gigabit Auto-Negotiation (No Link to
    Connected Device) section of Troubleshooting Cisco Catalyst Switches to
    NIC Compatibility Issues:


    Brad Reese
    2007 Cisco Salary Rates
    www.BradReese.Com, Jan 12, 2007
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