[ns] throughput about tcp aggregate flow

[qing zhang]

hi
In my experiment,there are tow tcp aggregate flow,each has ten tcp flows.the bottleneck is 10Mb.I use this method to calculate the average
throughput.For the sake of convenience,I suppose the n1,n2 is behind the bottleneck in the topology,and one aggregate flow pass n1,the other
aggregate flow pass n2,the time of simulation is 200s.I use the gawk to 
analyze the trace file.Plus the bytes of  all packet pass through n1 ,n2 respectively,I get sum1 and sum2.I use the formula 
sum*8/(1000000*200),here 200 is the time of simulation.in calculate,I use sum1 and sum2 substitute the sume respectively ,and get the average throughput ave1 and ave2.In my opinion ,the summation of ave1
and ave2 should equal or near 10Mb/s,which just be the botleneck,but actually,it always lower than 8.7Mb/s ,I think the result is not reasonable.because the two aggregates should cosume all the bottleneck. 
So how to calculate the throughput ,can someone give me some advice,
thanks a lot!
 



__________________________________________________
¸Ï¿ì×¢²áÑÅ»¢³¬´óÈÝÁ¿Ãâ·ÑÓÊÏä?
http://cn.mail.yahoo.com