Information About Interface Counters; Information About Link Flapping; Information About Port Security; Chapter 9 Port - Cisco Nexus 1000V Troubleshooting Manual

Information About Ports

Information About Interface Counters

Port counters are used to identify synchronization problems. Counters can show a significant disparity
between received and transmitted frames. To display interface counters, use the following command:
show interface ethernet slot number counters
See
Values stored in counters can be meaningless for a port that has been active for an extended period.
Clearing the counters provides a better idea of the actual link behavior at the present time. Create a
baseline first by clearing the counters.
clear counters interface ethernet slot-number

Information About Link Flapping

When a port continually goes up and down, it is said to be flapping, or link flapping. When a port is
flapping, it cycles through the following states, in this order, and then starts over again:
1.
2.
3.
To troubleshoot link flapping, see the

Information About Port Security

The port security feature allows you to secure a port by limiting and identifying the MAC addresses that
can access the port. Secure MAC addresses can be manually configured or dynamically learned.
For detailed information about port security, see the Cisco Nexus 1000V Security Configuration Guide.
Type of Port
vEthernet access
vEthernet trunk
vEthernet SPAN destination
Standalone Ethernet interfaces
Port channel members
To troubleshoot problems with port security, see the following:
•
•
Cisco Nexus 1000V Troubleshooting Guide, Release 5.2(1)SV3(1.1)
9-2
Example 9-11 on page 9-14.
Initializing—The link is initializing.
Offline—The port is offline.
Link failure or not connected—The physical layer is not operational and there is no active device
connection.
VM Cannot Ping a Secured Port, page 9-7
Port Security Violations, page 9-8
"Information About Link Flapping" section on page
Is Port Security
Supported?
Yes
Yes
No
No
No
Chapter 9 Ports
9-2.
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