[ns] current window size in TCP

[Priya Mahadevan <priya@cs.duke.edu>]

Hi,

Can someone tell me
what is the unit for the current window size
for a TCP/Reno agent ?
I have 2 nodes n0 and n1 connected by a
1Mb/100ms link. I attach a FTP application to
the Reno agent which sends 10MBytes to the
TCPSink node. (I have initialised my
packetSize to 1500 and window_ to 100).

But I have trouble figuring out the graph that I plot of current window
size against time. The graph looks OK, it takes about 85 secs to transfer
the file and I also get the sawtooth with an average current window size
of about 50. I attached a flow monitor to the link and measured the
bandwidth and after stabiizing, I get approximately 0.95 Mb/sec. However,
if I compute bandwidth from the graph of current window vs time, it
doesn't agree with 0.95 Mb/sec.  For if for example you look at a
particular point on the graph like at 50 secs, the window size is about
60. I assume this is 60 KB but I am not sure. Since the current window
size is 60, I can have 60KB of unacknowledged data in transit. But 60 KB/
200 ms gives me 2.4 Mb/sec which is way above my 1Mb link.

Can someone tell me the right way to interpret this ?
I don' know where I am making a mistake.

Thanks in advance,
Priya