DESERT

Both UwCBRModule and UwApplicationModule have the same method to compute the packet error rate:

double
UwCbrModule::GetPER() const
{
	if (drop_out_of_order_) {
		if ((pkts_recv + pkts_lost) > 0)
			return ((double) pkts_lost / (double) (pkts_recv + pkts_lost));
	} else {
		if (esn > 0)
			return (1 - (double) pkts_recv / (double) esn);
	}

	return 0;
}

esn is the expected sequence number and is updated with the sequence number + 1 of the last received packet. And pkts_lost is computed as follows inside the recv() method:

	if (drop_out_of_order_) {
		if (uwcbrh->sn() > esn) {
			incrPktLost(uwcbrh->sn() - (esn));
		}
	}

Meaning it also depends on esn.

In the case where drop_out_of_order is set to 0, if from a certain point of the simulation I don't receive any new packet, the per computation will be wrong because the receiver doesn't know how many packets were sent.
Example : If the sender transmits 100 packets but the receiver only gets the first 50 before the link fails, esn remains 50. The resulting PER is 1 - 50/50 = 0, which is incorrect (the actual PER is 50%).

The problem persists also in the case where drop_out_of_order is set to 1 because pkts_lost is based on esn.

Solution:
Remove this method compute the PER from tcl as the number of packets received over the sent ones (as we always do anyways).