Today on a whim I decided to pickup a Linksys WRT54Gv6 wireless router from Staples. It was on sale for $20 off and looked like the last one there. I’ve been looking at the DD-Wrt software for some time since I have an old junky wireless router buried in my closet at home. Unfortunately the old router I have cannot run DD-Wrt so when I saw this one on sale I thought I’d give the WRT54G a try.

Unfortunately, I didn’t realize I bought the crippled version of the good WRT54G since it now has only 2mb of flash memory rather than the 4mb the earlier versions had. Apparently the best version to get now is the WRT54GL because it contains the most flash memory and is meant for Linux. The version I bought has a proprietary O/S installed on it and I was slightly worried I wouldn’t be able to get linux on it, but after following some good instructions at the Scorpiontek website I managed to get it working really easily.

I’ve only have the new firmware on the router for a few hours but I already like it alot more than the stuff that it shipped with. Even with the micro version there are far more options to play around with. The most useful so far for me is the client bridge mode. At my girlfriends house, her Access Point (AP) is located down in the basement and we use the net mostly in her room on the second floor. Until now we had terrible connections up there but in client bridge mode we can make use of the more powerful radio on the AP and plug into it with wires. Seems to be working much more smoothly now than when we had several weaker clients connected in the same room. Perhaps ill try and make some graphs and show if there is an actual difference if I get some time.

Eventually I would like to try to play around with the DD-Wrt source and try to implement some of my wireless mesh ideas in a working device so I’ll see if i can mange with what I’ve got here. Additionally, I have a cool looking LCD panel that an electronics friend gave me so I’ll see if I can get some help hooking that into the router to display some useful information right on the router. I’ll post any progress I make or pictures of mods on the blog here.

I have found many people already who have had difficulty setting it up so maybe this will be of some help to someone. For this tutorial I am assuming you have installed the most recent version of Ubuntu (8.04). (At the time of writing)

Step 1: Update Ubuntu

Since it has already been a month or so since Hardy Heron has been released its probably best, if you haven’t already done so to update Ubuntu. The easiest way I’ve found is to go to System>>Administration>>Update Manager. Alternatively, you can enter this into the terminal:

Step 2: Download all of the required pieces to make ns2 work

Here is a list of archives required for ns2 to work properly (you can download them by clicking the links or just enter all of the commands in the code sections below for automatic download and untar). I saved each archive to the desktop so I could find each one easily but you could use anywhere you like.

1. tcl 8.4.14
2. tk 8.4.14
3. otcl 1.13
4. tclcl 1.19
5. ns 2.33
6. nam 1.13

Step 2.5: Install Ubuntu Packages

Before installing everything else, I have found that it is helpful to get a few packages from the ubuntu repositories or else it wont build correctly. Grab a cup of coffee it might take a while since kdebase-dev is somewhat large. I’m sure there is a way to do this with fewer packages however I know this works. If anyone figures out exactly which packages are required let me know so I can update this.

Step 3: Install tcl

Step 4: Install tk

Step 5: Install oTcl

Important Note: The ‘./configure –with-tcl=’ portion of the following two code fragments should point to the source files for tcl. If you have been following the guide by copying and pasting the previous commands what we have here will work just fine. Otherwise you will need to change this to point to the correct location of your tcl source files.

Step 6: Install tclcl

Step 7: Install ns2

You will likely get alot of warnings for deprecated conversions. Just ignore these or if you really are concerned about them visit the nsnam troubleshooting page. If you want to make sure your version of ns-2 is working correctly after the install you can run the validation test from within the ns2 source directory. You can do this by entering:

You should see that the test output agrees with the reference output. Congratulations you have a working version of ns-2 installed.

Step 8: (optional) Install nam

Note: if you get this error:

it may be necesary to do this:

You are now ready to start working with ns2 and nam. If you are like me and working on a new protocol or something you will want to start modifying the ns-2 source code and recompile again so you might want to keep that folder handy. The rest of the source can be safely removed as far as i know. Keep in mind after you have modified the source you will want to do another make install so that when you type ns in your terminal the version you just compiled is used.

Getting Started with NS2

These are some quick tips to get you started using ns2 if you are a beginner.

All example files are located in ns/tcl/ex. You can run these scenarios on ns2 using ns filename.tcl The best way to start is probably changing things in these files until you understand what is happening more thoroughly.

The output will usually be a trace file with a similar name: ex) filename.tr. Trace files can usually be viewed with a text-editor program. There are also tools to analyze the trace files and pull stats from them. These may require some tweaking however depending on the format of the trace file. Additionally, a nam output file for visualization may be generated as well. This will usually be named filename.nam. To view the visualization use: nam filename.nam

Useful Links

I thought it might be useful to add a section on useful links here since this article has become quite popular. If you would like to suggest a link feel free to contact me.

• Ns2 Wiki
• Marc Greis’ Tutorial
• NS Manual
• NS for Beginners (pdf)
• Common NS2 Installation Problems
• NS2 Wireless and Mobility Modules
• NS2 Mailing Lists
• NS2.33 Wireless MAC and PHY improvements