Consider the ESRT protocol, with the plot of event reliability $rvs.$ reporting frequency $f$ as given below.

Figure $1$: The effect of varying the reporting rate, $f,$ of source nodes on the event reliability, $r,$ observed at the sink.

For a given reliability threshold $R=4000,$ show the regions of:

$(NC,LR)=$ No Congestion, Low reliability

$(C,HR)=$ Congestion, High reliability

$\frac{?}{OO}R=$ Optimal Operating Region

Use assumptions and additional variables if needed.