Storm Control - Maipu

Today in this section, We will see about Maipu Switching storm control function. Many times, we need to configure this function at the time of deployment for switches, Majorly in service provider network this is must to ensure loop free and broadcast free network.

Storm control -

This command is used to strict the size of the broadcast flow permitted to pass on an Ethernet port. When the broadcast flow on the port exceeds the value configured by the user, the system discards the packets which exceed the limitation of the broadcast flow. In this way the proportion of the broadcast flow can be reduced to the limited range and the normal operation of network services is ensured.

Following types of the restricted packets can be configured:

Broadcast packet，broadcast；

Unknown multicast packet，multicast。

You can configure storm control for pps(packets per second) and bps(bits per second).

Syntax - storm-control {broadcast|multicast|unicast} {pps packets|bps rate-bps}

To configure storm control for bps(bits per second). The unit of bps is kbps and the granularity is 64kbps. The value range is 64-8000000, that is, 64kpbs to 8G.

After the configuration, the status of the storm control can be displayed via show  stormcontrol [portlist].

Default status: The storm control is not configured.

Storm-control action

This command is used to configure the action executed after storm suppression happens, that is, disable the port pr send TRAP alarm. To send TRAP, first enable snmp service and enable the corresponding switch.

The action types:

Disable port: shutdown;

Send TRAP alarm: trap;

 Let’s see this function in action with configuration - 

 Topology

 Test purpose:

We need to make sure, If switchport receive unknown broadcast and multicast. It will shutdown the port.

port 0/1

 port-type uni

 uni-isolate community

 storm-control broadcast pps 500

 storm-control multicast pps 500

 storm-control action shutdown

 ethernet uni-id UNI-port-0/1

 ethernet uni-type bundling

 exit

This configuration , if more than 500 packet per second multicast/broadcast.It will active the action (shutdown the interface)

### You can configure in bps also.

show run and show version information

  

All IOS for MP 3400 will support this feature. (released from 2009)

Captures

Case one(test the unknown broadcast packet)

Here we can see under the every second the software is sending 512 unknown broadcast packets to switchport and in switch, we have defined that : storm-control broadcast pps 500. In this time the switch interface port 0/1 automatically shutdown as we configured the action.

Output -

After that you can just use command no shutdown let this port UP.

Case two(test the unknown multicast packet)

When the port 0/1 receive overload multicast it will automatically shutdown the port and give you the information. This feature is one part of err-disable functions.

Tested on following IOS version:

MP3400: sp1-g-6.1.35(RL08-07).bin and 6.2.19.pck

Hope this report will help you..

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