Configuring Storm Control

Context

Excess broadcast, unknown multicast, or unknown unicast packets have a significant impact on network devices. To limit the rate of these packets, configure storm control on the interface that receives these packets.

When Jumbo frames are received by an interface, the bytes mode is recommended.

For S2720-EI, S5720I-SI, S5720-LI, S5720S-LI, S5720S-SI, S5720-SI, S5730S-EI, S5730-SI, S5735-L, S5735S-L, S5735S-L-M, S5735-S, S5735S-S, S5735-S-I, S6720-LI, S6720S-LI, S6720S-SI, and S6720-SI, when detecting unicast packets, a switch does not distinguish unknown unicast packets from known unicast packets. The packet rate detected is the sum of the rates of unknown and known unicast packets. When the storm control action is block, the switch blocks only the unknown unicast packets. This rule also applies to multicast packets.

Pre-configuration Tasks

Before configuring the storm control function, configure link layer protocol parameters for interfaces to ensure that the link layer protocol status on the interfaces is Up.

Procedure

Run system-view
The system view is displayed.
Run interface interface-type interface-number
The interface view is displayed.
Run any of the following commands:
- storm-control { broadcast | multicast | unicast } min-rate min-rate-value max-rate max-rate-value
- storm-control { broadcast | multicast | unicast } min-rate cir min-rate-value-cir max-rate cir max-rate-value-cir
- storm-control { broadcast | multicast | unicast } min-rate percent min-rate-value-percent max-rate percent max-rate-value-percent
Storm control is performed on broadcast packets, unknown multicast packets, or unknown unicast packets on the interface.
Run storm-control action { block | error-down }
The storm control action is set.
(Optional) Run storm-control enable { log | trap }
The system is configured to record logs or report traps during storm control.
(Optional) Run storm-control interval interval-value
The storm detection interval is set.

Verifying the Configuration

Run the display storm-control [ interface interface-type interface-number ] command to check the storm control configuration on an interface.

Follow-up Procedure

If an interface is in Error-Down state, you are advised to determine the cause first.

An interface in Error-Down state can be recovered using either of the following methods:

Manual recovery (after an Error-Down event occurs):

If a few interfaces need to be recovered, run the shutdown and undo shutdown commands in the interface view. Alternatively, run the restart command in the interface view to restart the interfaces.
Automatic recovery (before an Error-Down event occurs):

If a large number of interfaces need to be recovered, manual recovery is time consuming and some interfaces may be omitted. To avoid this problem, run the error-down auto-recovery cause storm-control interval interval-value command in the system view to enable automatic interface recovery and set the recovery delay time. Run the display error-down recovery command to view information about automatic interface recovery.

This method does not take effect on interfaces that are already in Error-Down state. It is effective only on interfaces that enter the Error-Down state after this configuration is complete.