Abstract:

When teaching our students (undergraduates, STEM - electrical engineering), one of the fields that cannot be “skipped” in last decade or even longer is computer networking. Convergence of different network technologies and protocols to common global TCP/IP-based networks (TCP - Transmission Control Protocol, IP - Internet Protocol) is something that urges future engineers to embrace at least basic knowledge of functional principles of those networks.

When it comes to computer networking, one (STEM student) should try to understand the principles in order to be able to make decisions and apply right approach when working on any network-related project. It is expected that an engineer or technician educated in STEM area has some deeper knowledge of it. Why? Because, as the Internet, most of all computer networks are based on the same protocols, called TCP/IP stack of protocols. This article is about showing an approach that, hopefully, simplifies teaching and increases level of understanding of how the network protocols work! In addition to standard lectures, we introduce computer lab examples based on open-source and free emulation tool called IMUNES (abbreviated - Integrated Multiprotocol Network Emulator/Simulator). Standard methods of real-life network analysis and tests in computer labs - using computers with standard operating systems, connected in local area network, usually Ethernet based - are also an valid approach, but when learning and especially trying to understand functional principles, such standard methods may include too much overhead and bring students out of focus. It is mostly because of modern operating systems continuously sending some control data to the network, but also because students should collaborate or centralise their work in lab exercises. We believe that an approach introduced in this article allows students to overcome that limitations and get better understanding faster. Of course, after validating and verifying their lecture based knowledge in that kind of labs, they can easily check it in standard environments too.

Our article will include short introduction to mentioned emulation tool, IMUNES, but most of the article content will be directly related to performing lab exercises. There will be a section shortly describing TCP/IP stack as currently most used protocol stack. Two main exercises related to very important, but most often hidden from end-users, protocol - ICMP (Internet Control Messaging Protocol) will be covered in depth, together with theoretical introduction and explanations - one exercise will show an example of basic usage of the well known ping command (using Echo Request and Echo Reply ICMP messages), while other exercise will try to show how to explain functioning of another often used command, traceroute. Both IPv4 and IPv6 networking-layer protocols are covered in exercises. The objective of this article is to show that students can get in-depth understanding of how basic tools like ping and traceroute and related protocols work, using simple and user oriented emulation tool and standard network analysis tools such as Wireshark. Due to the nature and architecture of introduced emulator, IMUNES, it will be shown that results are comparable to real-world (non emulated) network environments, as expected.

Keywords:

computer networks, IMUNES, emulation, simulation, computer lab, exercise, ping, traceroute