Watching for packet storms
Broadcast and multicast storms can greatly slow the network. To watch for impending broadcast or multicast storms, use the Activity Display tool. The Activity Display tool tracks occurrences of broadcast/multicast packets.
Prerequisite(s):  
Classic mode must be enabled.
 
On the Classic tab, in the Statistics group, click Activity Display.
Click the View button to choose a different layout.
Click Settings to further customize said layouts.
Most importantly, changes can be made to the update interval of the graph view and to thresholds of the plot view.
 
Results can be saved in a comma delimited file using File > Save > Save Data.
The indicator lines change color for easy viewing of specific network conditions. If an indicator line is yellow, the Activity Display is showing a network condition that is essentially idle (total net utilization is under 5%). Here, the percentage of broadcast or multicast packets may be high compared to actual traffic. However, because the traffic is so low, this condition is not statistically important.
If an indicator line segment is green, the Activity Display is displaying a normal network condition. If an indicator line segment displays red, the Activity Display is letting you know that a load condition exists. This is not necessarily a problem, but indicates that you should be aware of this condition.
Load conditions can mean different things depending on where the red, blue, or green lines appear. Typically, a red line means that a threshold has been overcome. Blue lines display on the side where the threshold may be an indication of trouble. By default, red lines are displayed if broadcast or multicast packets are representing more than 10% of total network utilization or if utilization goes over 35%.