How to measure the Network Link duration between two nodes?

[Samson Arun Raj]

I have create two mobile nodes in NS-3 for 1000 seconds simulation.

I need to measure the network link duration between these two nodes for every time interval T seconds.

What is formula to calculate?

I need to measure the Performance Metric for Time in (X-axis) vs Network Link duration in (Y axis). As the time increases every T seconds, the rate of change in network link duration should be measured between these two mobile nodes.