debugging the simulation script in ns ?

[Anurag <anurag@cs.ust.hk>]

Hi

I am using ns to simulate some simple network topology, using cbq. when I
run my script in ns I am getting some error that I am not able to
decypher, it looks some thing like given below:

0
ns: _o70 unknown-flow 1024 770 3 3: 
    (_o70 cmd line 1)
    invoked from within
"_o70 cmd unknown-flow 1024 770 3 3"
    invoked from within
"catch "$self cmd $args" ret"
    (procedure "_o70" line 2)
    (SplitObject unknown line 2)
    invoked from within
"_o70 unknown-flow 1024 770 3 3"



After I modified the code to take care of some flow ids, it is giving
segmentation fault.

Segmentation fault (core dumped)


How can I debugg my program, is there a step mode in ns so that I can run
my program and find out what is going wrong, or is there some other way to
debug it.


thanks in advance.


with Regards
Anurag,