Cyclic redundancy check (CRC)

Cyclic redundancy check (CRC) polls CRC errors for each port in the configured polling interval.

If the number of CRC error exceeds the configured threshold in a polling window, the configured action is taken. You can set the threshold in the range 1 to 10.

Note

This feature is enabled by default. The default threshold is 5.

Port CRC supports following actions:

Raslog: This is configured by default and the event are logged.
Port-shutdown: If port-shutdown is configured as action, the event is logged and the port shuts down. The interface state changes to port CRC down. To bring up the port, you must explicitly enable the port.

The port CRC is enabled using the crc enable command. The command is run from the system monitor port configuration mode.

device (config-sys-mon-port)# crc ?
Possible completions:
  action          Set Port CRC Monitoring Action
  enable          Enable Port CRC Monitoring (Default: Enabled)
  poll-interval   Set Port CRC Monitoring Poll-Interval
  threshold       Set Port CRC Monitoring Threshold

The command crc action allows you to set various actions. The command crc poll-interval allows you to set the polling interval. The command crc threshold allows you to set the crc monitoring threshold.

The show interface status command displays the port crc status.

device# show interface status
--------------------------------------------------------------------------------
Port         Status          Mode       Speed    Type            Description
--------------------------------------------------------------------------------
Eth 3/1      connected (up)  --         10G      10G-SFP-SR                     
Eth 3/2      adminDown       --         --       --                             
Eth 3/3      notconnected    --         --       10G-SFP-SR                     
Eth 3/4      port-crcDown    --         --       --

To view port crc status on a specific ethernet interface, issue the show interface ethernet command.

device# show interface ethernet 3/4
Ethernet 3/4 is port-CRC down, line protocol is down (port-crc down)
Hardware is Ethernet, address is 00e0.0c76.79e8
    Current address is 00e0.0c76.79e8
Pluggable media not present
Interface index (ifindex) is 415367190
MTU 1548 bytes
10G Interface
LineSpeed Actual     : Nil
LineSpeed Configured : Auto, Duplex: Full
Priority Tag disable
Last clearing of show interface counters: 13:19:17
Queueing strategy: fifo
Receive Statistics:
    0 packets, 0 bytes
    Unicasts: 0, Multicasts: 0, Bro

You can also view the port crc status by issuing the show ip interface brief command.

device# show ip interface brief

Interface              IP-Address          Vrf                     Status                    Protocol
==================     ==========          ==================      ====================      ========
Port-channel 1         unassigned                                  administratively down     down
Port-channel 2         unassigned                                  administratively down     down
Ethernet 3/1           10.3.1.1            default-vrf             up                        up
Ethernet 3/2           unassigned          default-vrf             port-crc down             down
Ethernet 3/3           10.3.3.1            default-vrf             up                        down
Ethernet 3/4           unassigned          default-vrf             administratively down     down

To view the port crc status on a specific ip interface, issue the ip interface ethernet command.

device# show ip interface ethernet 3/4
 Ethernet 3/4 is port-crc down protocol is down
 IP unassigned
 Proxy Arp is not Enabled
 Vrf : default-vrf