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Big problems with cisco SFPs

Discussion in 'Networks' started by ciscohelp, Oct 10, 2012.

  1. ciscohelp

    ciscohelp New Member

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    Hello All,

    I'm having one hell of a time with this problem and it's driving me crazy..

    Hardware: 4 Cisco 3750x switches in 2 stacks of 2. Each switch has a 10GB (SFP-10GB-SR)
    which is connected to its oppisite stack mate for a total of 2 10gb links. Theses two links
    are configured in a port channel (20GB total).

    Layout:
    -------------
    SWITCH1A--1ft/.5m_Patch_Cord--patchpanel--460ft/140m_Verticle_Cable_Run--patchpanel--3ft/.5m_Patch_Cord--SWITCH2A
    SWITCH1B--1ft/.5m_Patch_Cord--patchpanel--460ft/140m_Verticle_Cable_Run--patchpanel--3ft/.5m_Patch_Cord--SWITCH2B

    Problem:
    -------------
    The 10GB interfaces will not come active across the 140m cable. If I connect Switch1B to 2B
    Directly via the patch cables, the ports come active and work as expected. If I install a 1GB
    SFP across the 140m link it also works. The 10GB Interfaces however never come up, are not errordisabled
    or have any other abnormality.

    What I have done to fix:
    --------------------------
    Reboot all Switches
    Replace All Patch cables
    Move SFP to another port
    Shut/Noshut Actual interfaces and Portchannel
    Remove interfaces from portchannel, then above again.

    All Cables are OM3 Spec, are brand new and have been tested with a OTDR, fluke meter
    and have very minimal DB loss (1.1db+/-). All cable connections pass with excellent results.
    But the 10GB SFPs still fail to come active across the 140m cable.

    The OM3 spec and these SFP's (Orig. Cisco) are rated from 300m which is double the
    length of the installed cable.


    Can anybody help me with this before I have to have myself committed???
     
  2. Simonvm

    Simonvm Kilobyte Poster

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    Do you see any (red) light emitting from the fiber at the other end?
    Have you tried swapping your send and receive fiber? Sometimes the cable guy tends to mix them up...
     
    Certifications: MCITP: EST, MCDST, MCTS, A+, N+, CCNP, CCNA Wireless
  3. ciscohelp

    ciscohelp New Member

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    Thanks for the info/Reply..

    No, there is no light on the fiber, as the SFPs do not come active.
    The cable techs tested the cables and found no errors or x-overs. The 140m cable
    as mentioned is new, and the measurements so only 1-1.2 db loss. They are next to perfect.
     
  4. Simonvm

    Simonvm Kilobyte Poster

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    41
    How do you mean, do not become active? They should be emitting light from the moment the SFP is inserted in the slot.
    If you watch inside the SFP you will see a faint red light on one of the sides.

    They become active when you put a shorter fiber between them, right?
     
    Certifications: MCITP: EST, MCDST, MCTS, A+, N+, CCNP, CCNA Wireless

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