The CRC counter continues to increment, as shown in the show
interfaces gig output:
Force10>show interface gig 0/7
GigabitEthernet 0/7 is up, line protocol is up
Hardware is Force10Eth, address is 00:01:e8:07:e0:00
SFP present. Media type is ZX.
Internet address is not set
MTU 1554 bytes, IP MTU 1500 bytes
LineSpeed 1000 Mbit
ARP type: ARPA, ARP Timeout 04:00:00
Last clearing of "show interface" counters 13w5d19h
Queueing strategy: fifo
51040098567 packets input, 12649732603754 bytes
Input 50484710883 IP Packets, 50872183339 Vlans 0
21293513947 64-byte pkts, 16911511032 over
64-byte pkts, 1131757544 over 127-byte pkts, 2803601459 over 255-byte pkts,
5251066555 over 511-byte pkts, 3648648031 over 1023-byte pkts Received 0 input
symbol errors, 0 runts, 0 giants, 0
throttles, 12783 CRC, 0 IP Checksum, 0 overrun, 0 discarded
65507855048 packets output, 50346845285803 bytes,
Output 236700899 Multicasts, 1389966414
Broadcasts, 63881187735 Unicasts
Background / Explanation
The following issues have been shown to generate CRC errors:
Bad fiber cable
- This condition has been seen when a connected router interface,
with auto-negotiation disabled, was shut down without a link-down being detected
by the Force10 system. Some third-party devices continue to power on the
fiber port’s laser even though the port is in shutdown mode.
To troubleshoot a bad fiber cable, try reducing the attenuation.
To troubleshoot dirty optics, clean the optics at both ends, as described in
Cleaning and Inspecting Optical Fibres.
Try a different fiber cable and try connecting it to different ports.
Information to Collect if You Open a TAC Case
If you still would like assistance from Force10 Networks after
following the troubleshooting steps above, please use the
Create Service Request form on the isupport page and include the
following information if available:
Console captures showing the error messages
Console captures showing the troubleshooting steps taken and the boot sequence
during each step
Saved messages to a syslog server, if one is used.
Output from the show trace command
Output from the show tech-support