18.2.2 Configuring Storm Control

• Suppressing broadcast frames

  To prevent broadcast storms, set the reception rate of broadcast frames that can be received on an Ethernet interface. Since broadcast frames include ARP packetsand other frames required for communication, the reception rate should be set so that there is room for the frames normally used.

• Suppressing multicast frames

  To prevent multicast storms, set the reception rate of multicast frames that can be received on an Ethernet interface. Since multicast frames include IPv4 multicast packets, IPv6 multicast packets, control packets such as OSPF packets, etc. that are required for communication, the reception rate should be set to a sufficient amount considering the frames that are normally used.

• Suppressing unicast storms

  To prevent unicast storms, set the receive rate of unicast frames that can be received on the Ethernet interface. For the reception rate, set a value with sufficient room considering the frame that is normally used.

  Although the Switch uses the total number of received unicast frames for the detection of unicast frames, only flooded unicast frames are counted as frames to be discarded instead of being forwarded because their destination MAC addresses are not registered in the MAC address table. Especially when specifying port shutdown for storm detection operation, set a value with sufficient reception rate so that storm detection does not occur in the frame that is normally used.

• Operations when a storm is detected

  Specify the Switch operations to be performed when a storm is detected. You can select port shutdown, sending private SNMP notifications, and outputting operational messages for each port.

  • Blocking a port

    When a storm is detected on a port, deactivate the port. To activate the port again after recovery from the storm, use the activate command.

  • Sending private SNMP notifications

    Sends a private SNMP notification when a storm is detected and a storm is recovered.

  • Outputting operation messages

    An operation message is output and notified when a storm is detected and a storm recovery is detected. Note that a message must be output if a port is blocked.

Points to note

The mirroring of sent or received frames can be defined for Ethernet interfaces.

If a storm occurs on a port, the port is blocked.

Command examples

1. (config)# interface gigabitethernet 1/0/10

   (config-if)# storm-control broadcast level pps 50

   Sets the acceptable receive rate for broadcast frames to 50pps.

2. (config-if)# storm-control multicast level pps 500

   Sets the acceptable receive rates for multicast frames to 500pps.

3. (config-if)# storm-control unicast level pps 1000

   Sets the acceptable receive rate for unicast frames to 1000pps.

4. (config-if)# storm-control action inactivate

   Deactivates a port when a storm is detected on the port.