mLAB User Manual

So, you just designed your new mobile ad hoc network (MANET) algorithm/protocol/application/whatever and successfully evaluated its efficiency with extensive simulations. What is the next step? A field test of a prototype will show whether simulations were on the right track or not, but that’s a big leap to take; going from the simulator directly to the real thing.

That is why there are testbeds to bridge that gap. Testbeds are emulators, typically a great number of devices with wireless capabilities deployed in a large space and waiting for you to program them, experiment with them and test your work in almost realistic conditions. However, there are few who can afford to have such a facility in their lab. Usually, it’s possible to rent this equipment, run your experiments remotely and, then, receive the results and analyze them. The problem is that your work will be conducted under serious time constrains, especially if you are on a tight budget, not to mention that a lengthy learning curve could consume a significant portion of that budget.

That’s where mLab comes in. mLab is also a MANET emulator, a testbed, but the difference with other testbeds is that it is intended to operate in your lab. In brief, mLab’s software allows users to automatically generate arbitrary logical network topologies, in order to perform real-time performance measurements of routing protocols or network applications. And on top of that, it’s open-source!

1.2. Overview of mLab

The general idea of mLab is having a number of MANET nodes physically close to each other (inside your lab), but force them to “think” that they can only communicate with a selected few of them. That way, we can emulate a logical topology, on which we can run e.g. a routing protocol to analyze its behavior.

So, what does mLab need in order to work? First of all, there is the hardware. mLab is an emulator, not a simulator, so you have to have the necessary hardware equipment [For client: any Linux system with 1 wireless interface, 1 wired interface, for server: Linux x86 (Rec: Debian stable) with 1 wireless interface, 1 wired interface]. That means that each node should be a device that has a wireless (802.11a/b) interface, so that it can communicate with other ad hoc nodes and run MANET protocols. In addition, the device should also have a wired interface (Ethernet or USB), which is used for administrative purposes. In other words, mLab uses the wired interface to transfer files needed for its operation to and from the node, and manipulate its networking elements in such a way that will create the logical topology we want (kind of like blinders are used with horses to force them to see only part of the bigger picture J). That leaves the wireless interface free of any interference and, most importantly, emulates an actual MANET, which was the whole point all along.

Figure 1‑1: (a) physical links, (b) logical links between MANET nodes

You will need a PC to act as a server, which will run the main components of mLab and from which you will control all your nodes. All nodes must have an Ethernet (or USB connection using USB networking) connection with the server, probably through a hub.

Figure 1‑2: Logical diagram of mLab. We use the wired links (green lines) to manipulate the physical wireless links (dotted lines) and create logical wireless links (red lines)

1.3. Supported platforms

mLab was developed and intended only for Linux machines. In other words, any device that can run Linux and can support wireless and wired interfaces can run mLab. Currently, the following platforms have been tested and are supported;

ix86 (desktop and laptop PCs), running Debian Stable and kernel version 2.4.X (There are available already configured 2.4.27 kernels if anyone is interested)
ARM (iPAQ, CerfCube, Zaurus), running Familiar OS and Kernel version 2.4.X (There are available already configured 2.4.19 kernels if anyone is interested)

There are pre-configured kernels for all of the above at http://csrc.nist.gov/manet/ that only need to be compiled for the intended platform. Check the installation instructions for more information.

In case you haven’t figured it out already, since the ix86 architecture is supported and Linux can run even in 80386 machines (mLab requires, at least, Pentium II however), you can gather all those old PCs you intended to throw away, add a PCMCIA wireless card on each of them and set up a MANET testbed in your lab at a relatively very low cost!

1.4. Photographs of mLab

Figure 1‑3: Hardware for a mLab. You can see 11 CurfCubes and 1 laptop that are all connected to the mLab Server via a 10/100 Hub

Figure 1‑4: Another part of mLab. 2 PCs with PCMCIA wireless cards, a SONY ZAURUS, a COMPAQ iPAQ and a CurfBoard, all mLab nodes

Figure 1‑5: … Wireless networking …

1.5. mLab modules

mLab consists of these modules;

Network Configuration module, with which the user can assign Wired IP, Wireless IP and Wireless MAC to every node.
mNet (Create Scenario) module, which is responsible for generating random logical topologies based on user-defined rules.
Malicious actions module, where the user can select and optimize from a number of attacks against the network.
Network traffic generator (Create Simple Network Traffic), where the user can create simple traffic between nodes using a number of different protocols (UDP-TCP [sockets with any possible port available] and ICMP).
Network Information tool, where the user can view and set several options of the wireless network, such as signal strength, wireless network administrate fixtures, wireless adapter hardware and software info.
Sniffing (Network Sniffing Tool), which is a sniffing tool and allows the user to observe all overheard traffic and apply filters on it.

The next chapters describe, in more detail, how these features work.

1.6. GNU license

mLab is under the GNU license, which means that it’s open-source. Visit http://www.gnu.org/ for further details. So, you are free, welcome and expected to download mLab, use it, alter it, improve it, etc.

1.7. What mLab is NOT

A really important concept you must realize from the start is that mLab emulates a MANET at the network layer of OSI (layer 3) and above. That means that it has nothing to do with neither the physical nor the data link layer (layers 1 and 2). Don’t forget that the nodes will, most probably, be close to each other in your lab, so every node can “hear” every packet transmitted by any node, but ignores most of them, according to what mLab dictates. So, in order to avoid any future misunderstandings, mLab does NOT emulate a MANET at the data link layer, it emulates a MANET at the network layer. If you want to use mLab to test your data link protocol, unfortunately, you should seek something else and you can stop reading this manual (who likes manuals, anyway? J).

Another thing, which you should have in mind, is that mLab was designed and developed having security-related issues in mind. As a result, some of its aspects focus on security, rather than e.g. network performance. However, it’s an open-source tool, so you are free to alter it any way you see fit.

Also, since mLab is not a commercial release, you will find that it lacks extensive error control routines in its GUI (text-boxes, etc). You cannot damage any hardware, don’t worry, and just be a little careful with your input and with buttons that say stuff like “Send to node” (when you haven’t a node connected), if you want to avoid error tracking, which you probably do!!

Chapter 2: INSTALLATION

The installation of the mLAB is very simple. First of all you must be root. After that you extract the mLAB.tar.gz and you enter the mLAB folder. Then you should run the “./CHECK_ENV” script that will inform you whether or not you have the necessary applications in order to install the mLAB. The most important applications that you must have preinstall before you are ready to install mLAB are:

- Greaphviz [http://www.graphviz.org/]

- QT3 [http://www.trolltech.com/]

- Libpcap0.9.4 [http://www.tcpdump.org/]

- Expect [http://expect.nist.gov/]

- Sed ,fgrep,xargs,console (usually these are in the standard installation of any Linux system.)

When the “./CHECK_ENV” script finish without any errors then you are almost ready to run the “install.sh” which will actually compile the mLAB. First you must change the /root/.bashrc file and add these 3 lines:

- export MLABROOT=/usr/local/mlab or any other path of the directory that you wish the mLAB to install in.

- export PATH=$PATH:$MLABROOT/scripts:$MLABROOT

- export MLABSERVER=192.168.10.1 The servers wired IP (not the WIRELESS).

After editing the .bashrc file and restarting your console, you are ready to install the mLAB. Just run the install.sh script and follow the instructions.

Chapter 3: mLab

This chapter describes, in detail, what each GUI element of each mLab module does.

Before you start using mLab, you must deploy your network and assign each node with a wired IP and a wireless IP, as indicated in the installation instructions.

Note, also, that you should be logged in as root in your PC that acts as a server, in order for mLab to work properly.

3.1. Network Configuration

Figure 3‑1: Network Configuration module tab

In this tab you can declare your MANET nodes to mLab and transfer required files to the nodes. As you can see in figure 3-1, at the top left section, you can Add, Edit or Delete a node in mLab. Of course, you must know each node’s wired and wireless IP; otherwise, mLab won’t be able to find and communicate with the node. The right section of the tab is the list of all the nodes you have declared and their total number.

After, spitefully, planning the attack, give it an appropriately evil name at the bottom left section of the screen and add it to the attack list and save it, in order to repeat it anytime. You must only select your attack and press the ‘Start Attack’ button to unleash it! Then, you can use any network monitoring tool, like Ethereal, to find out what you have just done to the poor network…

3.4. Create Simple Network traffic

Figure 3‑5: Create Simple Network Traffic tab

Here, you can create a simple, constant data flow between two nodes in the network (peer-to-peer connection). Again, you should see a logical diagram of the network at the upper right section of the screen.

You can select the source and destination nodes, the protocol (TCP, UDP, ICMP), the port you will use, how many packets you will send and how long the delay will be between two consecutive packets. Like in the ‘Malicious Actions’ tab, you can save your traffic cases in a list. In the bottom part of the screen you can see a short description of the selected traffic case.

3.5. Remote execution command and quick network testing

Figure 3‑6: Create Network Traffic tab

This is a simple tool to check whether or not your new topology case has been successfully applied. Also, you can execute any command line command you wish on any remote node. Please note that while the remote command is being executed, the mLAB is being focused on it and no other mLAB fixture is available during the command execution.

Chapter 4: mLab side tools

mLab comes with two auxiliary tools that give general information about the network.

4.1. Network Information

Figure 4‑1: Network Information form

Not much to say here; this tool gives you information about the wireless characteristics of your network. Just select the node you want from the list at the top left section and push the ‘Get Info’ button. You can see and alter the transmit power, the WAP key it will use and the ESSID. The ‘Reset Malicious Node’ button cancels any malicious activity of the node and resets him to normal routing (if only it was that simple in real communication…). You can also see IP tables information, wireless routing information, etc.

4.2. mSniffing – Network Sniffing Tool

Figure 4‑2: mSniffing - Network Sniffing Tool

This tool is a Sniffer that operates in the nodes. First, you must select the node from which you will get the sniffing information and then push the ‘Go’ button to communicate with the node and receive this information. You will see a list of all the overheard traffic at the bottom left section of the screen. Unless you are permanently brain-damaged or your name is Neo, you might want to use the filtering options at the top section of the screen.

When you click on a packet, it is parsed and all information is presented in a more readable form, at the bottom right section of the screen.

mLAB User Manual

Written by

Aimilios Apostolopoulos and Manos Antonakakis

{aimilios,manos}@nist.gov

National Institute of Standards and Technology mLAB

3.3. Malicious actions

National Institute of Standards and Technology
mLAB