Which three statements accurately describe the factory-default storm control configuration? (Choose three.)

A.
Storm control monitors traffic levels for broadcast traffic.

B.
Storm control monitors traffic levels for unknown unicast traffic.

C.
Storm control drops all monitored traffic in excess of 80 percent.

D.
Storm control monitors traffic levels for multicast traffic.

E.
Storm control shuts down the interface on which the storm control level is exceeded.

Explanation:
Understanding Storm Control on EX Series Switches

A traffic storm is generated when messages are broadcast on a network and each message prompts a receiving node to respond by broadcasting its own messages on the network. This, in turn, prompts further responses, creating a snowball effect. The LAN is suddenly flooded with packets, creating unnecessary traffic that leads to poor network performance or even a complete loss of network service. Storm control enables the switch to monitor traffic levels and to drop broadcast and unknown unicast packets when a specified traffic levelcalled the storm control levelis exceeded, thus preventing packets from proliferating and degrading the LAN. As an alternative to having the switch drop packets, you can configure it to shut down interfaces or temporarily disable interfaces (see the action-shutdown statement or the port-error-disable statement) when the storm control level is exceeded.

The factory default configuration enables storm control on all switch interfaces, with the storm control level set to 80 percent of the combined broadcast and unknown unicast streams. You can change the storm control level for an interface by specifying a bandwidth value for the combined broadcast and unknown unicast traffic streams. You can also selectively disable storm control on the broadcast stream or on the unknown unicast stream.

Broadcast, multicast, and unicast packets are part of normal LAN operation, so to recognize a storm, you must be able to identify when traffic has reached a level that is abnormal for your LAN. Suspect a storm when operations begin timing out and network response times slow down. As more packets flood the LAN, network users might be unable to access servers or e-mail.

Monitor the level of broadcast and unknown unicast traffic in the LAN when it is operating normally. Use this data as a benchmark to determine when traffic levels are too high. Then configure storm control to set the level at which you want to drop broadcast traffic, unknown unicast traffic, or both.

Note: When you configure storm control bandwidth on an aggregated Ethernet interface, the storm control level for each member of the aggregated Ethernet interface is set to that bandwidth. For example, if you configure a storm control bandwidth of 15000 Kbps on ae1, and ae1 has two members, ge-0/0/0 and ge-0/0/1, each member has a storm control level of 15000 Kbps. Thus, the storm control level on ae1 allows a traffic rate of up to 30000 Kbps of combined broadcast and unknown unicast traffic.