I have looked through as much Cisco, and other, documentation as I could find on the subject, but I couldn't find a solid answer on this question.

The default action for an interface that exceeds the configured storm-control level is to drop the traffic. However, what happens to an interface when you configure one of the optional behaviors?

It would seem that the traffic would continue to be dropped, in addition to the configured behavior. But I can't find evidence of this. Here I've configured a storm-control action of 'trap', along with rise and fall thresholds.

storm-control action trap
storm-control broadcast level 40.00 30.00
storm-control multicast level 40.00 30.00
storm-control unicast level 40.00 30.00
  • You didn't configure drop. The configuration clearly shows trap, which is different.
    – Ron Maupin
    Feb 15, 2016 at 20:45
  • drop is a default, and it isn't clear if 'trap' replaces this behavior or is in addition to it.
    – skrap3e
    Feb 15, 2016 at 20:47
  • Trap still suppresses the traffic. another thing you should set with trap is the SNMP configuration, including the storm-control trap rate.
    – Ron Maupin
    Feb 15, 2016 at 20:54
  • Do you have documentation/support for your answer? Also, do you have an example, this sounds like a good practice.
    – skrap3e
    Feb 15, 2016 at 21:29
  • I don't have any documentation for that, but that is what actually happens. I think it would be a good practice if you have the infrastructure to support it. Here is an article about good switch habits which includes that: packetpushers.net/….
    – Ron Maupin
    Feb 15, 2016 at 21:40

3 Answers 3


Always blocking traffic, in your case all kind of multicast,unicast in addition.

Your choice can be shutdown port or send snmp trap, but all of it would be happen after blocking. cisco off doc


Storm control options have pretty descriptive names like shutdown or trap. Shutdown will shut the port down, and trap will send an SNMP trap.

When you have the drop option, the first number will be the point at which the traffic will be suppressed (dropped), and it will continue to be suppressed until the traffic drops below the second number, at which point it will again flow through the interface.

All three options will prevent excessive traffic, either by dropping it or disabling the port. Trap will also send SNMP traps. Depending on how you have SNMP configured, you could get a trap when a port is shut down by the shutdown option.

You can flood SNMP with the trap option, so you should configure the storm control trap rate in the SNMP configuration.

  • This is true, however doesn't address my question. The default action is drop, however it isn't clear if when option 'trap' is set if traffic is continued to be dropped after it exceeds rising threshold.
    – skrap3e
    Feb 15, 2016 at 20:46
  • It will send SNMP traps in the same fashion as the drop.
    – Ron Maupin
    Feb 15, 2016 at 20:46
  • What do you mean by "in the same fashion?" This is a little ambiguous.
    – skrap3e
    Feb 15, 2016 at 20:48
  • It will send traps when the upper threshold is reached, and it continues to do so until the lower limit is reached.
    – Ron Maupin
    Feb 15, 2016 at 20:56
  • But will it drop traffic, that is the question. A phone call would have been much easier ;) Thanks for your time Ron!
    – skrap3e
    Feb 15, 2016 at 21:28

cisco system is more help this program.

interface Te1/0/1
channel-group 1 mode active
description "Uplink to Core"
interface port-channel 1
class of service trust ip-dscp
switchport mode trunk
switchport trunk native vlan 10
  • 2
    This does not seem to answer the question at all. Please consider adding details on why you think this is helpful for the person asking this question.
    – Teun Vink
    Mar 17, 2016 at 10:34

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