2×2 Switch Simulation in Matlaab

2Ãâ€"2 Packet Switch Simulation Using Matlab Interim Report Contention, output-buffer, queuing process, analytical analysis, simulation Student Name: Deniz Ozdemir Email: [email  protected] qmul. ac. u Supervisor: Dr John Schormans Deniz Ozdemir ec09502 Interim report Contents Page 1. 1 Aim 1. 2 Methodology 1. 3 Objectives 2. Background 2. 1 Performance Evaluation 2. 1. 1 Measurement 2. 1. 2 Analysis/Simulation 2. 2 Packet Switched Networks 3. Introduction 4. Theory 4. 1 Queuing Theory 4. 1. 1 Queuing Model 4. 1. 1. 1 Concept of a queuing model 4. . 2 Queuing theory notation 4. 1. 3 The M/M/1 Queue 4. 1. 4 The M/D/1 Queue 4. 2 Switching 4. 2. 1 Switching Concept 4. 2. 1. 1 Internal Link Blocking 4. 2. 1. 2 Output Port Contention 4. 2. 1. 3 Head Of Line Blocking 4. 2. 2 Time Between Arrivals 4. 2. 3 Counting Arrivals 4. 2. 4 The Queuing Behaviour Of Packets In Output Buffers 4. 2. 4. 1 Calculating The State Probability Distribution 5. Analytical /Simulation Results 5. 1 2Ãâ€"2 Swi tch 5. 1. 1 Analytical Results 5. 1. 2 Simulation Results 5. 2 4Ãâ€"4 Switch 5. 2. 1 Analytical Results 5. 2. Simulation Results 5. 3 8Ãâ€"8 Switch 5. 3. 1 Analytical Results 5. 3. 2 Simulation Results 5. 4 16Ãâ€"16 Switch 5. 4. 1 Analytical Results 5. 4. 2 Simulation Results 6. Conclusion 7. Project Management 7. 1 Risk Analysis 7. 2 Gant Chart 8. References 9. Appendix 2 2 2 2 2 2 2 3 3 3 3 3 4 5 5 7 9 9 9 9 11 11 13 14 14 15 15 15 17 19 19 20 22 22 23 25 25 26 28 28 28 28 28 29 1 Deniz Ozdemir ec09502 Interim report 2Ãâ€"2 Packet Switch Simulation Using Matlab 1. Aim Build a simple 2Ãâ€"2 packet switch simulation using Matlab and study its performance 1. 2 Methodology ? Test out simulation on fundamental 2Ãâ€"2 switch element. ? Then expand it. 1. 3 Objectives ? Learn about Matlab. ? Learn about simulation. ? Build simple test model and try it. ? Build 2Ãâ€"2 element in Matlab. ? Simulate results. ? Process results. ? Simulate any new results required. ? Write report. 2. Background 2. 1 Performance Evaluation When networks are designed, the goal of the performance evaluation is that to determine the best effect of the equipment sed. Methods for performance evaluation are measurement techniques , analysis and simulation. [3] 2. 1. Measurement For measurement methods real networks are used for experimentation. The advantage of direct measurement of network performance is that no detail of network operation is excluded but experience hard to test performance limits. Customers won’t like it when you crash the system. [3] 2. 1. 2 Analysis/ Simulation In comparing analysis and simulation, the main factors to consider are the accuracy of results, the time to produce results, and the overall cost of using the method. Advantage of analytical solutions is that they are quite good fit to reality and produces results quickly. However assumptions required to define equations and parameters and they can be very complex. Simulation provides system representation to required precision. However simulation can be time and cost demanding. [3] 2 Deniz Ozdemir ec09502 Interim report 2. 2 Packet Switched Networks In a packet switched network all nodes interconnected by directed links. Packets are routed independently. Packets enter the network at a specific node where they may be queued in a buffer to wait for an outgoing channel to become free. This continued in a hop by hop manner until the packets finally arrive at their destination. Packets may arrive the same destination by taking different routes. That increases efficiency of transmission resources. Also queued packets in the buffer will cause a variable delay and throughput, depending on traffic load. Basic network is shown in figure 1. [1] Figure 1: Packet Switched Network 3. Introduction Contention in a switch affects the performance of a switch. To prevent this some switching techniques are developed. One of the most common switching techniques is the one with output-buffered switch. In this report, queuing process of performance evaluation, for such a switch is done analytically first than simulation analysis is done using Matlab. In the end of the report comparison of two results is done. 4. Theory 4. 1 Queuing Theory Analysis of the queuing process is basic and essential part of the performance evaluation. Because queues are form in a network when there is a high demand on limited resources. 4. 1. 1 Queuing Model Packets arrive at a queuing system to be served for a certain time. If service is not immediately available they wait for service in a storage area (buffer). After a certain length of time, they are served and leave the system. Basic queuing system is shown in figure 2. 3 Deniz Ozdemir ec09502 Interim report Figure 2: Schematic diagram for a single server queuing system [3] Also basic queuing relationship is shown in table below General q=?. W=?. = + Table 1: Basic queuing relationship Single Server ? =?. q=W+? 4. 1. 1. 1 Concept Of A Queuing Model Let N (t) be the number of packets waiting in the queue plus the one who is being served (1,2,3). A series of packets arrive at instants T1