Basics about Traffic Storm control in Switches and Routers

Today I am going to talk about the Traffic Storm control on the devices. Here in our example we will discuss and configure the basic configuration of Traffic Storm control  A traffic storm happens when packets flood the local area network and generating unnecessary traffic and humiliating network performance. The Traffic Storm Control feature avoids LAN ports from being interrupted by a broadcast, multicast, or unicast traffic storm on physical interfaces.

Confirm that you design independent storm control policers for each of the broadcast, multicast, and unknown unicast traffic types. Traffic categories that do not have a configured policer will not be traffic controlled. For example, Broadcast traffic will not be traffic controlled if you do not configure a storm control policer for it.

Traffic storm control inspect each traffic type for which you permit traffic storm control in a second traffic storm regulator intervals. Within an interval, when the entrance traffic for which traffic storm control is permitted reaches the traffic storm control level that is designed on the port, traffic storm control declines the traffic until the traffic storm control interval ends.

Fig 1.1- Traffic Storm Control

Below is the configuration example showing how to enable broadcast address storm control on a port to a level of 10 percent. When the broadcast traffic exceeds the configured level of 10 percent of the total available bandwidth of the port within the traffic-storm-control interval, the switch drops all broadcast traffic until the end of the traffic-storm-control interval on the switch.

Storm Control for Broadcast Traffic

RouteXP_Sw1# configure terminal

RouteXP_Sw1(config)# interface gigabitethernet2/0

RouteXP_Sw1(config-if)# storm-control broadcast level 10

The Below example shows how to enable unicast storm control on a port with an 80-percent rising suppression level and a 50-percent falling suppression level

Storm Control for Unicast Traffic

RouteXP_Sw2# configure terminal

RouteXP_Sw2(config)# interface gigabitethernet2/0

RouteXP_Sw2(config-if)# storm-control unicast level 80 50

Similarly, as we configured the storm control for unicast and Broadcast in the switches, we can also configure the Traffic storm control in the routers. Below is the basic configuration for Traffic Storm Control on the interface for Broadcast, Unicast and Multicast traffic in ASR 1000 series router.

Configuring Traffic Storm Control

RouteXP_R1(config)# interface GigabitEthernet0/1

RouteXP_R1(config-if) # no ip address

RouteXP_R1(config-if) # negotiation auto

RouteXP_R1(config-if) # service instance 20 ethernet

RouteXP_R1(config-if-srv) # encapsulation dot1q 1-4094

RouteXP_R1(config-if-srv) # storm-control unicast cir 1000

RouteXP_R1(config-if-srv) # storm-control broadcast cir 120000

RouteXP_R1(config-if-srv) # storm-control multicast cir 7600000

RouteXP_R1(config-if-srv) # bridge-domain 1