First of all, let’s look at the statistics of active traffic on ports:
show interface ethernet counter rate
Then we’ll look at the packet counters, especially pay attention to the BroadCast (pkts) column:
show interface ethernet counter packet
For a specific port, we will execute the command to view the statistics of the network interface several times:
show interface ethernet 1/25
And let’s pay attention to how the incoming and outgoing values of the broadcast packets change, if they do not change, then the broadcast packets do not go through this port, if the digit increases rapidly, then maybe there is a broadcast storm.
If necessary, we will enter the competing mode and set the limit of transmitted broadcast packets in kilobits (minimum value 1) for the required ports:
config Interface Ethernet1/1 storm-control broadcast 50 Interface Ethernet1/2 storm-control broadcast 50 Interface Ethernet1/3 storm-control broadcast 50 ...
Note that with a low broadcast bandwidth limit, DHCP broadcast requests from clients can also be blocked.