berkeley: # SUCH DAMAGE.

introducing ns

software by Lloyd Wood

I learned to use the network simulator ns-2, and spoke at a VINT ns retreat.

I gained my doctoral thesis and some of my publications from using ns-2. If I can do it knowing that little about ns, then you can too. You'll even be able to succeed without my help -- I get emailed questions from many new users of ns, which I don't have time to read or think about, let alone answer. Do not email me your questions about ns. Use the ns-users list. If you're a student emailing about your ns problems, please do not expect a reply. You're not my student. (I haven't used ns3 - though I predicted ns3. My only recent ns activity was chairing the WNS2 workshop in 2008.)

If you're wondering about the worth of using ns-2 and having to learn that weird Tcl language... Tcl is quite common, and Tcl is on Cisco routers.

For viewing satellite simulations, satellite network drawing scripts are available. 4-up and pdf versions of tutorial slides are available.

Home of ns and users mailing list at ISI. Report ns bugs there. If you have a question about using or installing ns, ask the ns-users mailing list. That's what it's for; I'm not actively paying attention to ns or that list myself.

Material answering questions that are asked regularly:

and display page of results in order
A framed version of this service is available.

ns was developed as part of VINT (old pages).

learning ns

Marc Greis' ns tutorial is an invaluable introduction. It's now maintained by the ns developers, who have added a wireless chapter. Read the OTcl tutorial. There's now a multimedia introduction, but since it requires a RealAudio browser plugin on a Windows box I haven't tried it. Official documentation is included in the distribution - and now it's in HTML as well. Subscribe to the ns-users mailing list and search for relevant information before asking questions on the list. Using Edit/Find... in Acrobat on a pdf copy of the ns documentation is recommended.

Introducing aspects of TCP using ns - a very nice tutorial using the RFC793edu TCP. See also further work in the NIUNet project. ns tips and tricks from Aaron Striegel.

tracking the ns codebase

Read the change history. They've taken over maintenance of xgraph - hurrah.

Tcl debug (1.7, gzipped tarfile) in case of problems with new 1.9.x version; according to the ns change log 1.9.x was only supported as of 21 January 1999, and nam was upgraded later. Caution pays off...

other ns work

Here is an old list of third-party additions (many now documented on the ns contributed code wiki page). As I'm not actively following the ns-users list, not everything mentioned to that list is given below:

Variations on the theme of ns:

Parallelising simulation:

Useful links:

ns people

This guide to ns people now seems current. The ISI staff page is useful.

The dup script from Haobo Yu is useful for managing shared installations; here are instructions. These days, Kun-chan has taken over nam development from Haobo.

some ns people: John. Tom. Sally (old). Deborah Estrin. Lee Breslau's trace converter (see also video traces). George.

nam in action

Here are some old screenshots of nam showing some simulation development, building static moment-in-time topologies using traditional ns nodes:
Lloyd Wood (
this page last updated 18 August 2005