Do check Things to know about Fiber SFPs and Fiber types. before proceeding to know more on the terms used.

Troubleshooting Steps for Fiber Connection Issues

1. Transceiver Specs Mismatch:

• Ensure GBICs on both ends match in specifications, e.g., "10GB SR 400m SFP+."

• Verify both ends have matching specs of "SR 400m SFP+."

• Use compatible cables.

• Confirm the distance between nodes is within the rated limit.

2. Cable Type Mismatch:

• For Short Reach (SR) rated transceivers, use appropriate Multi-mode Fiber (MMF) cables that meet the GBIC specifications.

• For Long Reach (LR) or Extended Reach (ER" transceivers, use Single-mode Fiber (SMF) cables. Ensure cables rated for SMF  connections are used.

3. GBIC Compatibility with Devices:

• Refer to the optics datasheet from the respective vendor to ensure compatibility with switches, routers, or Access Points (AP).

• Consult System Engineers(SE) /Vendor Technical Assistance Centers(TAC) for assistance if unsure about the appropriate selection.

4. Hardware Fault on Connection Port/Interface, GBIC, or Cable:

• If the link does not come up, follow these steps:

  • Swap from port A to port B:

    • If the port comes up:

      • Check if ports A and B are configured similarly.

        • If yes, it is likely a port fault.

        • If no, match the configurations and test again.

    • If the port does not come up:

      • Swap the GBIC with a known working one:

        • If the link comes up, it is likely a GBIC fault.

        • If not, the issue is likely with the cable.

• Isolate hardware faults through substitution tests.

5. Cyclic Redundancy Check (CRC) Errors:

• CRC errors can occur if the fiber run is too long or if there are excessive bends or coils in the cable.

• To avoid CRC errors, ensure:

  • The fiber run does not have excess coiled cable.

  • Minimize bends in the fiber.

• If despite ensuring this, the CRC count is seen increasing try steps mentioned cause type (4) to isolate it further.

6. Weak Signals Received:

• Signal strength issues can arise if the cable run exceeds the rated limit or if the incorrect cable type is used.

• To ensure strong signals:

  • Use the correct cable type.

  • Verify the distance is within the rated limit.