This example demonstrates how to display active links in a network. An active
link is created when a packet gets delivered directly from one node to another.
Active links become inactive over time unless they are reinforced by new packets.

The adhoc wireless network contains a source node, a destination node, and a
number of intermediate nodes. The source node continuously pings the destination
node while all nodes move around randomly.

If you run the dynamic example in express mode until 2s, then you should see a
number of black arrows between the network nodes showing the currently active
links. These active links represent the communication that happened between the
DYMO routing protocols to determine the route from the source node to the
destination. After the route has been established, it is used for a while
without sending further routing protocol packets. If you continue the simulation
in fast mode until 10s, then you should see how these links fade away and become
inactive. Meanwhile the source node continuously sends ping packets to the
destination node through the established route. This is shown by the arrows
representing the active links along the route.