GBIC moved from Cat 3508 --> Cat 6513 shows wrong media type

Discussion in 'Cisco' started by Hoffa, Sep 18, 2006.

  1. Hoffa

    Hoffa Guest


    This weekend I tried to move a fiber connection from one Catalyst 3508
    to our central Catalyst 6513 equipped with a 16 port GBIC module
    (WS-X6516A-GBIC). What I thought would work was to remove the GBIC
    (G5486 LH/LX) along with the fiber connection and mount the GBIC in an
    available slot in the 6513. However the media type of the GIBC is now
    shown as LH instead of LX as was present in the 3508 and the link is
    shown as down/down
    I cannot find any indication that this can be controlled using console
    commands on the 6513. Has I missed something or do I have to get a new
    GBIC? As far as I know the other end of the fiber connection is out of
    my control.
    Our IOS is version 12.2(18)SXF3

    Fredrik Hofgren
    Hoffa, Sep 18, 2006
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  2. Hoffa

    Brian V Guest

    LX/LH is the same thing. Reverse the fibers and see if you get link.
    Brian V, Sep 18, 2006
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  3. Hoffa

    Sam Wilson Guest

    If he moved the GBIC and fibres together then that wouldn't be a
    problem. Is a 3508 old enough not to do autonegotiation? If so he may
    have to configure the port on the 6513 - "speed nonegotiate" is the
    interface command, I think.

    Sam Wilson, Sep 19, 2006
  4. Hoffa

    Brian V Guest

    Fiber GBICs don't negotiate, at least I have never seen one that does,
    please correct me if I'm wrong, supporting documentation as well please.
    There are 2 different styles of GBICs, the original which had little
    release levers on the side, those you did not need to remove the fiber to
    remove the GBIC. Then there were these cheesy POS ones that had this stupid
    little wire type bar that you had to lift to remove them, on those you
    needed to remove the fibers.
    A GBIC is a GBIC is a GBIC, they work in all chassis, there is nothing
    platform/model specific about them. Never seen one fail (not saying they
    don't <G>). There are only a few things that can prevent them from coming
    1, They need to be reversed.
    2, The port is admin down (but then it would be amber).
    3, The port is error disabled (never seen a fiber error disable, could be
    disabled if bpdugaurd was on).
    4, Bad fiber, doubtful where this worked before, but I suppose the patch
    cable could have been damaged when it was moved.
    Brian V, Sep 19, 2006
  5. Hoffa

    Sam Wilson Guest

    Golly, no! The GigE standard says that you should always negotiate and
    if you fail then the interface doesn't come up. That's to prevent the
    duplex mismatches that plague 10/100M ethernet. Prestandard products,
    such as the Cisco 12000 family GigE boards don't negotiate so if you
    want to connect them to a 6500 then you have to turn off negotiation on
    the 6500. You then have to remember to turn negotiation back on again
    if you later connect that same 6500 interface to a standard device.

    I don't have a reference to the standard but this is a clue:

    The second type is an SFP (a Small Form factor Package GBIC, GBIC stands
    for something like GigaBit Interface Connector) and is much more
    commonly referred to that way.
    Not true. Some Cisco platforms don't (or didn't) support at least one
    version of the Cisco 1000base-T GBIC (it takes a higher current than the
    optical ones). GBICs from different manufacturers cannot be reliably
    mixed (largely due to FUD, it seems). For instance a 3Com GBIC will
    probably work in a Cisco chassis but the type will not be reported
    correctly (it's always been blank when I've seen it) and a Cisco GBIC
    simply won't work in any of the 3Com switches we've tried them in
    (though 3Com have such a bewildering array of kit that I couldn't rule
    out them working in some). Here's some info:


    Cisco GigaStack GBICs and other things are different again. There's a
    product overview page here:


    Here's Cisco's policy on non-Cisco GBICs:

    Note: Cisco-approved GBIC modules have a serial EEPROM that contains
    the module serial number, the vendor name and ID, a unique security
    code, and cyclic redundancy check (CRC). When a GBIC is inserted in the
    switch, the switch software reads the EEPROM to check the serial number,
    vendor name and ID, and recompute the security code and CRC. If the
    serial number, the vendor name or ID, security code, or CRC is invalid,
    the switch places the interface in an error-disabled state.
    Note: If you are using a non-Cisco approved GBIC module, remove the
    GBIC module from the switch, and replace it with a Cisco-approved

    They do. :)
    5, check negotiation (see above)
    6, clean the fibre ends (very important for single mode cabling).

    Sam Wilson, Sep 19, 2006
  6. Hoffa

    Bod43 Guest

    Errr, no.

    There are two types of GBIC as described. Brian is not using
    the term GBIC to mean an arbitrary interface adaptor module thingy.
    He means a GBIC.

    I have heard the word GBIC used as a term for an arbitrary
    interface adaptor module thingy so I understand
    your reasoning.
    Bod43, Sep 19, 2006
  7. Hoffa

    Sam Wilson Guest

    OK, I've never seen a traditional GBIC with a wire latch.

    SFPs definitely have them, and in several places [1] SFPs are referred
    to as "Small Form-Factor Pluggable (SFP) GBIC Module" (yes, Pluggable
    not Package - sorry). So SFPs *are* GBICs with a "stupid little wire
    type bar that you [have] to lift to remove them". :)


    [1] here are a few - Google for "SFP GBIC" to find lots more:
    <"SFP GBIC">
    Sam Wilson, Sep 19, 2006
  8. Hoffa

    Brian V Guest

    This is an interesting topic/conversation to me, please don't take
    anything I'm saying wrong. I would love to be proven wrong on this and find
    a way to bring up legacy customers shy of using media converters.
    I do not believe the FIBER GBICs (we are talking what the OP has,
    5484's, 5486's or 5487's) follow the GigE standard, these might have even
    been before the standard. Again, I believe that their speed/duplex cannot be
    changed at all. They are 1000, that's it, plain and simple. I have done
    numerous searches on them and all I see mentioned is 1000base. I also just
    tried this is a lab, going from a 3550 with a 5484gbic to an old 2924M with
    a 100M fiber port, the link will not come up. While this sure as heck isn't
    definative, it does support my thinking. You can google groups on people
    trying to bring up new switches to their older devices which were only 100M.
    One thingthat I am finding which supports your statements is that they do
    support the speed nonegotiate command, but my thinking here is that it is
    nonnegotiate for flow control, not speed as indicated by the "speed" in the
    actual command. Another supporting tidbit is the fact that there is no
    duplex settings to manipulate, if it did follow the standards that should be
    a configurable parameter as well.

    Again, was refering to what the OP has which are 5484's, 5486's or 5487's.
    He came from a 3508 there are no other fiber GBIC's available for it.

    Was refering to yet again what the OP has, not SFP's, not GigsStacks. They
    are Cisco GBIC's, not 3com, extreme foundry or anyone else. They are not
    platform independant and are a standard accross all of their platforms that
    accept that size/model GBIC.

    I'm sure they do! LOL
    Brian V, Sep 19, 2006
  9. Hoffa

    Brian V Guest

    I was strictly refering to what the OP had. There are tons of different
    model GBIC's out there. I should have been more clearer (great english huh?
    I can shoot ya a pic if you'd like! I hate these friggin things! <G> Got a
    few of them here in my lab. I'll trade you for some of the other ones so you
    Brian V, Sep 19, 2006
  10. Hoffa

    Bod43 Guest

    I worked with GBICs extensively about 7 years ago and at
    that time there were quite a few failures.

    As to the autonegotiation issue. As far as I know Fiber Optic
    Ethernet ports each only offer a single speed.

    In the 10 and 100 days this was because the different standards
    specified quite different wavelengths and the physical optics
    and devices had to be different.

    I don't know how GBE is vs the others though.

    Constraining a port to a single speed though does not
    prevent it Autonegotiating. That is exchanging mesages about
    capability with its neighbour.

    In the Fibre Optic GBE case they will both say 1000 FD
    and then they will happily go to work.

    comp.dcom.lans.ethernet may have something
    or if you ask a question there Mr Seifert may be around
    or you could buy his book/get the IEEE Standard.

    My guess is that the Standards committee may have made
    Autonegotiation compulsory even though in some cases
    it is never going to be needed in order to simplify
    the Standard. I don't, I hasten to add, know.

    It is in the same veign interesting to note that the GBE standard
    included Half Duplex operation as a possibility however
    I believe that HD implementations are non-existent.
    I suspect that the Cisco Stacking GBIC is HD but it is intended to
    interoperate only with others of its kind and as such may
    not follow any standards at all.
    Bod43, Sep 19, 2006
  11. Hoffa

    Sam Wilson Guest

    OK, let me clarify. The negotiation is done by the GigE interface logic
    and is basically independent of the kind of GBIC or other PHY installed.
    I agree that most, if not all, GBIC based GigE systems don't negotiate
    speed, but they do negotiate duplex and flow control. (It turns out
    that 1000base-T systems cannot operate without negotiation turned on;
    other 1000base-X systems have it on be default but are allowed by the
    standard to have it configured off.) Here's a description for CatOS but
    there ought to similar things in the IOS manuals:


    In the example we have here there is a 6500 with a standard Cisco
    1000base-SX GBIC (that'll be a 5484) connecting to a Cisco 12000 1-port
    GigE interface. That also has a GBIC but according to the C12000 data
    sheets it seems to be a special part. No change of speed (or duplex)
    but we do have to turn of negotiation to make the link come up.
    Yes - agree. Apologies if I misled you.
    Yes. From the URL above:

    "With Gigabit Ethernet ports, autonegotiation is used to exchange
    ... duplex information (even though Cisco Gigabit Ethernet ports
    only support full-duplex mode)."
    OK, the second type isn't an SFP. :) But none of the 54xx series has
    the wire latch, does it?
    I missed the OP saying 5484/6/7. Those do seem to be interchangeable
    (see that URL above) but there are lots of others that Cisco make or
    made that aren't, so in general a GBIC, even a Cisco one, is not a GBIC
    is not a GBIC.

    Sam Wilson, Sep 19, 2006
  12. Hoffa

    Sam Wilson Guest

    OK, feel free to send a photo - I'll keep an eye on my spam traps. I'll
    decline the offer of a swap, if you don't mind. :)

    Sam Wilson, Sep 19, 2006
  13. Hoffa

    Brian V Guest

    Email sent. Let me know if you don't recieve them, I can put them in an FTP
    for you. Are you sure you don't want to trade? <G>
    Brian V, Sep 19, 2006
  14. Hoffa

    Sam Wilson Guest

    Sam Wilson, Sep 20, 2006
  15. Hoffa

    James Guest

    3, The port is error disabled (never seen a fiber error disable, could be
    I have, caused by a link flap, fixed with "no errdisable detect cause
    link-flap" :)

    James, Sep 21, 2006
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