Issue with Cisco Catalyst 4948-10GE fiber connection not functioning.
Issue with Cisco Catalyst 4948-10GE fiber connection not functioning.
You don’t have to restart it when updating settings. Are you clearing the configuration or keeping the existing one? Checking inventory, showing VLANs, status, logs, and interface details should help. Which fiber cable are you connecting? What transceiver model is being used? Did you try swapping the pairs so RX becomes TX?
When working with fiber connections, sometimes you need to switch the two fibers at one end manually so they don’t just emit light at each other. The fiber patch cable should display a color flag (a small yellow or white ring) or letters (A and B) on each strand. If the left side shows yellow or A, it should match the right side. For clarity, please share photos of the patch cable if you're unsure.
Inventory List
- Model: "Switch System", Description: Cisco Systems, Inc. WS-C4948-10GE 1 slot switch
- PID: WS-C4948-10GE
- VID: FOX1243GX5Z
- Name: Linecard(slot 1)
- Description: 10/100/1000BaseT (RJ45), 10GE (X2) Supervisor with 48 10/100/1000BaseT ports and 2 10GE X2 ports
- PID: DS-X2-FC10G-LR
- Vendor: Cisco
- VLANs: Active status, 190, 208, 230, 602, 1002, 1003
- Ports: All configured with appropriate duplex and speed settings
- Power Supplies: Two units listed (PWR-C49-300AC, PAC15150PD6)
The fiber module on the opposite side is connected to the computer, and the fiber patch cable you're using is a standard type designed for this connection.
The cable link: https://www.amazon.com/gp/product/B001B1...le_o03_s00 This device is the transceiver: https://www.ebay.com/itm/CISCO-compatibl...2684234830 I've tested them in two different NICs, including one with a Dell R620 built-in
It seems everything should work smoothly. Have you attempted exchanging the fibers at one end? You'll need to remove the clip securing them in a specific position. This task is likely simpler at the SC end, especially with larger connectors.
Review “show int te1/49 transceiver” and “show int te1/50 transceiver,” then verify the “Optical RX Power.” If it’s near -20 or lower, it likely isn’t picking up any light from the other side—possibly due to transmitter issues, cable problems, or a polarity mismatch that should have been caught by swapping ends.
Displays -2.1 and -2.5 Spoiler Switch>show int te1/49 transceiver ITU Channel not available (Wavelength not available), Transceiver is internally calibrated. If device is externally calibrated, only calibrated values are printed. ++ : high alarm, + : high warning, - : low warning, -- : low alarm. NA or N/A: not applicable, Tx: transmit, Rx: receive. mA: milliamperes, dBm: decibels (milliwatts). Optical Optical Temperature Voltage Tx Power Rx Power Port (Celsius) (Volts) (dBm) (dBm) --------- ----------- -------- Te1/49 39.2 0.00 -2.1 -2.5