Sensor network track

1.1    Module H2: Introduction to Internet Protocol

This module, taught on 26^th September (morning) covered basics of IP networks. Instructor was Ms. Monika Machnik (ITE). Course duration was 5 hours. The course material included:

Case study of an existing IP-based sensor network The 7-layer model Layer 2 and layer 3 addressing schemes Routing – main concepts Layer 4 protocols. On the left: Ms. Monika Machnik (ITE) explaining IP routing.

 1.2    Module H3: IP Embedded & Security

This module, taught on 26^th September in the afternoon, covered the following topics:

• Internet Protocol in sensor networks – overview of off-the-shelf solutions for creating IP-enabled embedded systems
• Security environment in IP networks – a series of case studies showcasing common security problems in network infrastructure
• Introduction to cryptographic services – an overview of basic cryptographic techniques
• Challenge of secure code – an overview of typical programming errors resulting in security vulnerabilities.

1.3    Module H4: Environmental monitoring systems

This was a 90-minute presentation from Ms. Justyna Woś from OMC Envag company, which is a distributor of environmental monitoring systems of leading manufacturers such as Hach-Lange and OTT. The presentation covered existing off-the-shelf solution for water monitoring, and was intended to provide ESRs with overview of real-world environmental monitoring systems.

1.4    Module L2a: IP Networks

In this module, students have assembled and configured off-the-shelf network equipment to create an operational IP-based network. The equipment included:

• Cisco Catalyst 2950 switches
• Mikrotik Routerboard RB2011UAS-RM routers
• Mikrotik Routerboard SXT 5nD r2 point-to-point wireless stations
• IBM Lenovo T61 laptops.

Mikrotik equipment has been chosen due to low cost and popularity in wireless ISP installations in Central Europe.

The software used included:

• Putty - free implementation of Telnet and SSH client
• WinBOX - Secure GUI/ Graphical Client used to configure MikroTik Appliances
• Small HTTP Server - a web server, and also Mail server, DNS server, FTP server, Proxy server
• Tftpd32 - free application which includes DHCP, TFTP, DNS, SNTP and Syslog servers as well as a TFTP client
• Wireshark - network protocol analyzer.

Network topology and assembled equipment are shown in figures below. The core network (red part) consisted of four MikroTik routers. Connections between core routers have been realized using Ethernet cables and wireless point-to-point links at 5GHz (operating as layer 2 bridges).  OSPF has been used as dynamic routing protocol due to ease of configuration. Dynamic routing has been demonstrated by introducing faults (i.e. disconnecting cables) after the network has been set up. Four leaf networks (green) have been connected to the core network. Students could study network behavior by means of programs such as ping, traceroute and Wireshark protocol analyzer.

It should be noted that the exercise had a strong collaborative focus, as different students have been assigned roles in configuring different devices which had to work together correctly.

Below: network topology and OSPF routing status.

1.5    Module L2b: IP Applications

The purpose of the module has been to demonstrate to students basic concepts related to programming of TCP/IP applications.

A scripting language AutoIt! for Microsoft Windows platform has been chosen due to its ease of use. Students have been tasked with writing a simple TCP client program and a simple TCP server program; netcat program has been used for testing. Subsequently, students have achieved TCP-based communication in pairs (one running the client, the other running the server).

Wireshark protocol analyzer has been used to study network exchanges. Finally, design patterns for multi-user servers have been discussed. Discussion of UDP-based communication has been dropped due to time constraints. On the left: ESR Katarina Cvejin studying a TCP connection using Wireshark protocol analyzer.

 1.6    Module L3: IP Sensor Networks

The aim of the module was to familiarize ESRs with basics of microcontroller programming for use in building sensor networks, i.e. creating sensor nodes.

Arduino development platform has been chosen due to high popularity and small learning curve. Each of students has been given a set of Arduino boards including: a microcintroller board, a network interface board (Ethernet), a board for connecting sensors.

Students have also been given different sensors and actuators, such as: potentiometers, joysticks, LEDs, electric motors, temperature sensors, Hall effect sensors (magnetic field sensors), ultrasound distance sensors.

Each of the students has implemented the following set of programs:

• flashing LED
• sensor readout / motor control
• basic TCP server / basic TCP client.

After the ESRs have constructed the basic building blocks, a second part of the exercise was started. Students were given a small self-driving robot. The task has been defined as follows:

Equip the robot with an Arduino board, a magnetic field sensor and a distance sensor Prepare a second Arduino board with a connected joystick Propose a network protocol for robot control Write client and server software allowing control of the robot using a joystick, and sensor readout over an IP network Use the robot to find a neodymium magnet, by driving around while monitoring sensor readouts. On the left: Robot used during the exercise.

1.7    Module L4: Cryptography

The goal of this module was to familiarize students with basic cryptographic techniques by means of a hands-on demonstration. Students have been provided with a set of computer programs implementing basic cryptographic operations:

symmetric stream cipher (RC4 algorithm) symmetric block cipher (AES algorithm) hash function (MD5 and SHA1 algorithm) asymmetric encryption (RSA algorithm). On the right: Example screenshot of the program used - calculation of message digest and message authentication code.

Students, working in pairs, had to implement secure message exchanges using the above programs. Specifically, the exercises included:

• exchange (i.e. encryption, transmission, decryption) of a message encrypted using a symmetric cipher with pre-agreed key
• bit flip attack against stream cipher
• calculation and verification of hash-keyed message authentication code (HMAC)
• exchange of messages using public-key cryptography (RSA)
• digital signatures using the RSA algorithm.

Finally, students have been asked to design a message exchange protocol providing: encryption of message contents using a symmetric algorithm, key exchange using asymmetric algorithm and message authentication.

Group photo after completing the exercise, left-to-right: Srdjan Ajkalo (ESR), Monika Machnik (instructor, ITE), Katarina Cvejin (ESR), Aleksandar Pajkanovic (ESR), Mitar Simic (ESR), Krzysztof Zaraska (instructor, ITE).