[ns] File format explain

Dear all,

I am new to NS2. And try to figure out the easy example now.

The example now has following scipt:

set mtcpsink_0 [new Agent/TCPSink]
$mtcpsink_0 set_filename tcpap_sink_0

which would generate a file, obviously.

But I just could not figure out what the file stands for?

The file is like this format:

1 0.171731 40
2 0.270314 1500
3 0.392966 1500
4 0.744979 1500
5 0.779175 1500
6 0.882837 1500
7 1.027826 1500
8 1.095344 1500

I could understand about tr file since there are many examples from the
internet. But this confuses me.

Could any one help me about that?

Thanks.

Brs,
James