This window appears when you choose Port > Flooding Control on the menu bar. You can also click here to launch it. Use it to configure storm control on a device.
Begin by selecting a device from the Host Name list. Depending on the device you select, you see a subset of these tabs:
When you finish configuring storm control on these tabs, click OK to close the window.
By default, the switch floods packets having unknown destination MAC addresses to all ports in the VLAN. Flooded traffic does not cross VLAN boundaries, except for multi-VLAN ports, which flood traffic to all VLANs to which they are connected.
Some configurations do not require flooding. For example, a port with only manually assigned addresses has no unknown destinations, so flooding serves no purpose. Therefore, you can disable the flooding of unicast and multicast packets on a per-port basis.
To disable flooded traffic of unicast and multicast packets:
By default, broadcast storm control is disabled. To enable it:
By default, unicast storm control is disabled. To enable it:
By default, multicast storm control is disabled. To enable it:
The numbers in the Suppression Level columns are storm control thresholds. Each threshold represents the percentage of the total available bandwidth of the interface. For example, a broadcast suppression level of 100 percent means that no limit is placed on broadcast traffic.
If the threshold of a traffic type is reached, traffic of that type is not forwarded in that interface. Forwarding resumes when the incoming traffic falls below the threshold.
To change a suppression level on an interface:
This table explains the settings on the Broadcast Storm, Unicast Storm, and Multicast Storm tabs. It applies to Catalyst 2900 XL and 3500 XL switches, and to Catalyst 2950 switches, with exceptions that are noted following the table.
Interface (read-only) |
Identifies the port: Fast Ethernet, Gigabit Ethernet, or ATM, the module or slot number (0, 1, or 2), and port number. |
Action State | Specifies whether an action is taken during a storm, and if so, what action is to be taken. Set this parameter to Filter to filter traffic during a storm; set it to Shutdown to shut the port down during a storm; or set it to Disable so no action is taken during a storm. |
Action Status (read-only) |
The current state of filtering on the port. Filter status can be active forwarding, active blocking, active shutdown, or inactive. |
Trap State | Specifies whether a trap is enabled or disabled. Set this parameter to
Enable to notify the SNMP trap manager when a threshold is crossed. Note: Be sure to configure a trap manager (System > SNMP Management) if you set this parameter to Enable. |
Trap Status (read-only) |
The current state of a trap on the port. |
Rising Threshold | Enter a number from 0 to 4294967295 (packets per second) to determine
when to activate storm control on the port. The default is 500. Make sure you set the rising threshold higher than the falling threshold. |
Falling Threshold | Enter a number from 0 (packets per second) to the rising threshold setting to determine when to deactivate storm control on the port. |
Packets (read-only) |
Reports the number of packets per second arriving at the port. |
Traps Sent (read-only) |
Reports the number of traps that have been sent. |
Catalyst 2950 exceptions. For these switches, Rising Threshold and Falling Threshold are replaced by the Upper Utilization and Lower Utilization, and Packets is replaced by Current Utilization, also a read-only column. By default, Action State is Disabled, and both Upper and Lower Utilization are 100.00. If you change Action State to Filter and do not change the utilization values, they are changed for you by token amounts: Upper Utilization becomes 99.99; Lower Utiliztion becomes 99.98. For meaningful filtering, change the Upper and Lower Utilization values to reflect the filtering thresholds you want; Action State will automatically change to Filter.