[ns] Throughput of CBR over TCP

[김병길]

Hi all,

 

I perform simulation of TCP using NS-2 simulator.

I already read all mails about CBR over TCP.

But, I really not understand about TCP mechanism when CBR is used.

 

1. use following TCP parameters :

1)       CBR packetsize : 500

2)       TCP packetsize : default

 

When I start CBR traffic of 500kbps, I can measure throughput of TCP.

The result is 2.2Mbps! Is it possible?

 

I know that TCP ignore packetsize upper layer and TCP has own estimation of
stable link and suitable time to send the packet.

But, my problem is that TCP does not wait the whole size from CBR

It seems that TCP sends own packetsize with CBR interval.

 

So, my question is why this is happened? and what is the possible problem?

Or, is it my mistake?

 

Thanks in advance.