2×2 Packet Switch Simulation
Aim 1. 2 Methodology
Packet Switched Networks
Concept of a queuing model
Queuing theory notation
The M/M/1 Queue
The M/D/1 Queue
Internal Link Blocking
Output Port Contention
Head Of Line Blocking
Time Between Arrivals
The Queuing Behaviour Of Packets In Output Buffers
Calculating The State Probability Distribution
Analytical /Simulation Results
Interim report 2×2
Packet Switch Simulation Using Matlab
Test out a simulation on fundamental 2×2 switch element. Then expand it. Learn about Matlab. Learn about simulation. Build a simple test model and try it. Build a 2×2 element in Matlab. Simulate any new results required? Write a report. When networks are designed, the goal of the performance evaluation is to determine the best effect of the equipment sed. Methods for performance evaluation are measurement techniques, analysis, and simulation. Measurement For measurement methods real networks is 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.
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. The advantage of analytical solutions is that they are quite a good fit for reality and produces results quickly. However, assumptions required to define equations and parameters and they can be very complex. Simulation provides system representation to the required precision. However, simulation can be time and cost demands. 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 at the same destination by taking different routes. That increases the 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.
Figure 1: Packet Switched Network 3.
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 an output-buffered switch. In this report, the queuing process of performance evaluation, for such a switch is done analytically first than simulation analysis is done using Matlab. At the end of the report comparison of the two results is done.
Queuing Theory Analysis of the queuing process is basic and essential part of the performance evaluation. Because queues are formed in a network when there is a high demand for limited resources. 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. The basic queuing system is shown in the figure.