[ns] Measure the traffic for flow

[Ken]

Hi, everybody,

I refered to Marc's tutorial for the method to measure the transmission
rate.
The example used three sinks to get the bytes every period.

It, of course, worked, but however when I transfer it to my own work,
the bytes are always "0".

My questions are:

1. Should the "Agent/LossMonitor" work with specified peer Agent? (It seems
to be so.)

2. If I want to measure the rate in the middle node instead of the end node,
this may not work.

Thanks for any suggestions !

Ken