[ns] NS vs. OPNET on simulation speed and simulation of large network

[Chi-Jiun Su <csu@hns.com>]

Dear Sir/Madam,

We're currently using OPNET for the end-to-end simulation of satellite
networks and simulation seems slower as we add more users.

Some sources are claiming NS is faster than OPNET and so we're thinking
of switching to NS.

In order to make correct decision for us, Could you answer the following
questions?

** Is NS releally faster than OPNET? (Any fair comparison is done?)
 If so, how much?

** Can NS simulate more nodes than OPNET (simulation of large networks)?

**What other advantages NS has over OPNET in addition to the following:
# NS is Free of charge
# NS is used by Top-notch research work like TCP and therefore OPNET is
lagging behind NS in new TCP stuff.
# NS can be run in LINUX and so it is possible for parallel/speedup
simulation


Thanks in advance.

Chi-Jiun Su
Advanced Development Group
Hughes Network System
Germantown MD 20760  USA