There are several tools that can help with this. These are basically network packets that run into each other because of excessive traffic. If a high traffic load job such as tape reading or backup from one machine to another is going on, you may see a rise in collisions. Normally there should be none. Don't be alarmed by collisions, unless there is no apparent reason for them.
Collisions can also be a sign that some line is failing somewhere in the network.
The activity lights on the hub will flicker with network activity. When the XMidas system is running, you will see a flicker on about a 1 second interval as data is passed, parsed, etc. When a Chart or Nav program is drawing or active, you will see an increase in network traffic. If an FTP transfer or other cross network transfer is occurring, the light will be on much more solid. Note that when in port, the light is always flickering, as it is also showing HMSC's network traffic.