Practical Experiment with KivaNS: A virtual Laboratory for Simulating IP Routing in Computer Networks Subjects.

Transcription

1 Practical Experiment with KivaNS: A virtual Laboratory for Simulating IP Routing in Computer Networks Subjects. F.A. Candelas, P. Gil AUROVA Automatics, Robotics and Computer Vision Group Contents Introduction Free open-source software for the simulation of computer networks Features needed d for a new application for simulating IP routing KivaNS to simulate IP Architecture Main features Using and simulating with KivaNS Teaching computer networks at the University of Alicante Practical ca experiments. e Student Opinion Evaluation using KivaNS Conclusions and Demos index m-icte 2009 Virtual Presentation 182 1

2 Introduction In the scope of the technical courses and careers based on communication technologies, the use of virtual laboratories is very common. For example: Laboratories for simple simulations and remote access of resources. Advantages Experimentation and practical learning of difficult concepts. Flexibility of time-tables. Access to limited equipment Autoevaluation systems Virtual laboratories can be also applied in the Computer Networks to enable students realize practical exercises without the necessity of access to real networks. KivaNS as an original development environment to teach and learn the different topics about Computer Networks. General aspects A free open-source software. Simulate computer networks connected with the TCP/IP architecture without real equipment. User-friendly and a compressible graphical interface. Applied as support for the student in the University of Alicante and other universities and technical institutes in the world INTRODUCTION Contents Introduction Free open-source software for the simulation of computer networks Features needed d for a new application for simulating IP routing KivaNS to simulate IP Architecture Main features Using and simulating with KivaNS Teaching computer networks at the University of Alicante Practical ca experiments. e Student Opinion Evaluation using KivaNS Conclusions and Demos index m-icte 2009 Virtual Presentation 182 2

3 Free Open source There are applications to evaluate the performance of a network, to simulate the working of a specific protocol or LAN, to simulate a dynamic routing of packets of data, etc. COMMERCIAL SOFTWARE FREE SOFTWARE It is more complete than free software. It has more user-friendly interfaces than free software. It has a high cost because they are target to professionals Example: Bosom Netsim by CISCO Programming: Require programming to prepare simulation and get results. Based on programming languages which are not quite intuitive. Graphical user Interface: It is not homogeneous. Many times, it is basically an animation to display results. Example: Ns-Network Simulator, J-Sim Network Simulator, Cnet Network Simulator Contents and aspects that cover. It does not consider different link layer technologies neither advanced routing aspects.. Example: IP Routing Simulator, TCP Control Flow Simulator for Simulation of Computer Networks Contents Introduction Free open-source software for the simulation of computer networks Features needed d for a new application for simulating IP routing KivaNS to simulate IP Architecture Main features Using and simulating with KivaNS Teaching computer networks at the University of Alicante Practical ca experiments. e Student Opinion Evaluation using KivaNS Conclusions and Demos index m-icte 2009 Virtual Presentation 182 3

4 Features needed Free software: Can be used by our students or other people without any cost. Portable software The source code has to be available to be modified d as well as flexible to improve it with new modules. This fact permits that the application be updated with new network technologies and protocols. Java is a good option. User-friendly graphical Interface The student of a Computers Networks subject should be centred in the operation of the networks, and he should not spend time in programming. The target of software must be IP routing simulation Several technologies for the link layer have to be considered. Our Proposal: KIVANS (Kiva Network Simulator) for Simulation of Computer Networks Contents Introduction Free open-source software for the simulation of computer networks Features needed d for a new application for simulating IP routing KivaNS to simulate IP Architecture Main features Using and simulating with KivaNS Teaching computer networks at the University of Alicante Practical ca experiments. e Student Opinion Evaluation using KivaNS Conclusions and Demos index m-icte 2009 Virtual Presentation 182 4

5 Architecture KivaNS is composed of three main blocks programmed completely in Java which can run in different platforms and operating systems: Simulation engine and classes that implement the available equipment and networks: It is based on a simple discrete event manager which attends and schedules events from the modules that implement the available equipment and networks. The equipment modules also access to other modules which manages the communications in the different layers of the network architecture API (Application Programming Interface): It facilitates the use of the simulation modules from different Java applications. It is independent from the graphical user-interface. Comprehensive graphical environment To use the simulation modules without the need of programming. KivaNS to Simulate IP Architecture Architecture of 3 Blocks: Block 2: API objects (some of them) Block 1: Simulation engine and modules: Block 3: Graphical user-interface KivaNS to Simulate IP m-icte 2009 Virtual Presentation 182 5

6 Main Features I The main features that KivaNS offers in comparison to other free open-source applications are the following: Complete graphical user-interface To draw network schemes and configure the parameters of the equipment and networks. Support for different layers for the network architecture The current version has several link layer technologies in addition to IP and other auxiliary protocols. A modular architecture It facilitates to include new networks, additional equipment, and even new layers for the network architecture. The configuration of interfaces and IP routing tables is very similar to the routing tables of real operating systems. It is possible to configure the MTU (Maximum Transmission Unit) of the link layer and evaluate the fragmentation of the packets of data. KivaNS to Simulate IP Main Features II The simulation manages the addresses of the link layer in addition to the IP addresses To do this, the ARP protocol (Address Resolution Protocol) has been also implemented. ICMP (Internet Control Message Protocol) to resolve common networks problems, like in the real networks was implemented The more frequent ICMP error messages have been implemented. It is also possible to disable specific errors. In addition to, it is possible to schedule several transmissions to be simulated send packets of data inside ICMP messages of echo (similar to the command ping ). Networks can be configured to generate specific or random errors The simulation can be carried out either step by step or full During the simulation, a trace of the frames and packets which are involved in the scheduled transmissions is displayed. KivaNS to Simulate IP m-icte 2009 Virtual Presentation 182 6

7 Main Features III Up to now, in KivaNS have been implemented the following layers and modules of the TCP-IP network architecture: Two kinds of the Ethernet link layer: Layers and protocols A simplified version of the original IEEE with CSMA/CD access over a bus or a hub topology. Switched IEEE 802.3, with link layer bridging of frames. IP (Internet Protocol): IP addressing and routing. IP fragmentation. IP broadcast. Three kinds of networks devices, in addition to wires and network buses, can be configured and simulated: Computers, routers and switches. Properties of a router KivaNS to Simulate IP Using and Simulating Creating and Simulating in simple steps: Step 1: To draw a network scheme. Step 2: To validate the design and configuration of network to find important errors in the interfaces, routing tables or connections. Step 3: To schedule different data transmission between pairs of computers: User can specify parameters such as the IP source and destination addresses, the size of the data and the option of fragmenting data. Step 4: To start the simulation, and perform it step by step or fully KivaNS to Simulate IP m-icte 2009 Virtual Presentation 182 7

8 Contents Introduction Free open-source software for the simulation of computer networks Features needed d for a new application for simulating IP routing KivaNS to simulate IP Architecture Main features Using and simulating with KivaNS Teaching computer networks at the University of Alicante Practical ca experiments. e Student Opinion Evaluation using KivaNS Conclusions and Demos index Practical Experiments Exercises about ARP, IP and ICMP protocols: Experiments over real network in the laboratory: The students work from the laboratory at the University The teachers configure the network devices available the laboratory to create a real network implemented physically. Students use a open source network protocol analyzer called Wireshark and other tools to generate and analyze traffic of packets in a real network. Different free software tools are used. Teachers assist students in the experiments. Students answer questionnaires about aspects of these protocols. The same experiments using KivaNS: The students can work from home or another place. The students draw a scheme of a network and they configure the objects which represent networks device so they create a virtual network implemented with KivaNS. Only KivaNs is needed. The students run KivaNS and simulate packets in different ways. Situations. The students answer the same questions that they did with real network Teaching Computer Networks with KivaNS m-icte 2009 Virtual Presentation 182 8

9 Student Opinion I Statistics studies about the use of KivaNS from interviews: Interviews have been made by 35 students of Networks Courses during the last year, although 43 did experimentation with KivaNS. In the interviews, students have given their opinion like users answering 15 questions. The questions have covered several topics and aspects. The main conclusions of this questions are: Problems: The 52% of students have not had any kind of problems with KivaNS, and only 30% has had some problem during the execution of the application. Interface: The 53% students think that the interface is very intuitive and it has easy handling, against 26% students who think that it is neither better nor worse than others. Handling: The 9% students think that is complicated, difficult or it requires of a certain effort to learn to hand it. Furthermore, the 13% students t do not give their opinions in this aspect. Stability: The stability while software is running, is considered robust by 9%, very good by 26%, medium by 26% and bad or quite improvable by 21%. The 17% students do not give their opinion about this aspect. The most positive Features valued: Free and open code by 61% of students. Teaching Computer Networks with KivaNS Student Opinion II Student opinion about how KivaNS help in the understanding of TCP-IP network architecture: Opinion of the students of Computer Networks subjects in University of Alicante about the advantages that KivaNS offers to help in the understanding of ARP, IP and ICMP protocols. D determines how of good KivaNS is to design and to simulate configurations of routing IP C measures the satisfaction level to use it to understand general concepts and aspects of network B is the general valuation of the application A is the aid that provides KivaNS to pass the subject of Networks Teaching Computer Networks with KivaNS m-icte 2009 Virtual Presentation 182 9

10 Evaluation with KivaNS I Evaluation of different aspects of Networks Courses with the use of KivaNS: Two types of experiments have been resolved with KivaNS and without KivaNS. The experiments were about how work ARP and ICMP protocols. The valuation of the learning has been done over 43 students of University of Alicante who have been chosen voluntary. The same experiments have been resolved without KivaNS for the same students. In this case, the experimentation has been made over a real network devices configured in a laboratory. Evaluation of student s learning using KivaNS and real Laboratory Teaching Computer Networks with KivaNS Evaluation with KivaNS II Example of experiment and questions answered (I). Step 1: Draw network scheme Step 2: Configuration PCs Step 3: Configuration Routers and validate interconnection Teaching Computer Networks with KivaNS m-icte 2009 Virtual Presentation

11 Evaluation with KivaNS III Example of experiment and questions answered (II). Step 4: Simulate Example of packets and frames displayed the simulation Example to configure the event which sends a packet with 1000 bytes. Step 5: Example of questions to student ARP-Proxy Exercise 1 PC_A run the command ping -n All the ARP-tables are empty. ARP Exercise 2 PC_B run the command ping -n All the ARP-tables are empty. Teaching Computer Networks with KivaNS Contents Introduction Free open-source software for the simulation of computer networks Features needed d for a new application for simulating IP routing KivaNS to simulate IP Architecture Main features Using and simulating with KivaNS Teaching computer networks at the University of Alicante Practical ca experiments. e Student Opinion Evaluation using KivaNS Conclusions and Demos index m-icte 2009 Virtual Presentation

12 Conclusions The great majority of the students consider that KivaNS is good software to learn these protocols without experimenting in a real network. Our students emphasize the facility to and setup use it, like an advantage in contrast to other applications of simulations that they know. KivaNS, and specially their graphical user interface, can aid to students to prepare the learning of TCP/IP in home or in another place apart from the laboratory of our University. The simulation API is more appropriate to develop degree projects and for post-degree courses. The application is free and open source software, and their capabilities can be expanded. In addition to the University of Alicante, KivaNS is being using in many faculties and institutes of Spain and South America, to teach network subjects of for degree projects. RESULTS Demos See Video 1 (Click here): CREATION A NETWORK SCHEME See Video 2 (Click here): CONFIGURATION PROPERTIES OF NETWORK DEVICES. See Video 3 (Click here): SIMULATION OF PACKETS TO ANSWER EXERCISE1 RESULTS m-icte 2009 Virtual Presentation

13 People who use Kivans University of Alicante, Alicante (Spain) University of Las Palmas, Gran Canaria (Spain). National University Daniel Alcides Carrion (Perú). University of Cordoba, Cordoba (Spain) EAFIT University, Medellín (Colombia). Latin University of Costa Rica (Costa Rica). University of Computer Sciences (Cuba). Coordination of Development CGTI UdeG, Jalisco (Mexico) Others. RESULTS Practical Experiment with KivaNS: A virtual Laboratory for Simulating IP Routing in Computer Networks Subjects. F.A. Candelas, P. Gil End Thanks for your attention AUROVA Automatics, Robotics and Computer Vision Group m-icte 2009 Virtual Presentation