Using link lines
Link lines are used to graphically illustrate the network link, or Interface service, between two devices. Link lines can also show the status of device services via associated active monitors.
The following example shows a map with link lines displayed.
In the graphic above, there are two link lines connected by a dot in the center of the line between the two devices. This shows that the devices are linked in both directions. This is done by repeating the process above from the second device, back to the first. Now, when one of the links goes down, you can see on which side the problem occurs.