tracefile interpretation

It is some what tough and is called as trace analysis. For doing this we have to have good knowledge about ns2 trace file formats.

Filter the necessary events from the trace file using scripting languages like tcl, perl, Python and awk or shell scripts or any other languages like C, C++, Java and prepare two column data file (one is for x and another is for y). now call xgraph with the data file as follows.
# xgraph mydata.txt

here the mydata.txt will contain the two column data.