[ns] Question on Link Failure

[w.huang at reading.ac.uk]

Greetings,

I can run the simulation TCL script for the Scenario 2 (the Appendixes from
http://www.ensc.sfu.ca/~ljilja/ENSC835/Spring02/Projects/feng/Final_report.p
df). And I have made a little modification on the script, including to show
the topology graph.

But I have some problems. Firstly, when the data flows are transmitted
within the MPLS domain, all of them become black (actually they are
differently colorful outside of the domain). But all the LDP message packets
are not affected.

Secondly, if I simulate a link failure, for instance, between LSR1 and LSR4
from 1.5 second by adding "$ns rtmodel-at 1.5 down $LSR1 $LSR4", an error
would come out. But if I use this line for other scripts, it is ok. It seems
that, for instance, '$ns at 0.2 "$src0 start"' together with '$ns rtmodel-at
1.5 down $LSR1 $LSR4' is ALRIGHT, but that, for example, an error will come
out for '$ns at 0.0 "constraint-based-routing 1100 $LSR1 9 1000K"' and '$ns
rtmodel-at 1.5 down $LSR1 $LSR4'.

I hope you can help me solve it. Cheers!

Best Regards,
Hunter