MATLAB SIMEVENTS RELEASE NOTES Betriebsanweisung PDF herunterladen (Seite 106)

5 Designing Paths for Entities

5-16

Model a Packet Switch

In this section...

“Overview” on page 5-16

“Generate Packets” on page 5-17

“Store Packets in Input Buffers” on page 5-18

“Rout Packets to Their Destinations” on page 5-19

“Connect Multiple Queues to the Output Switch” on page 5-20

“Model the Channels” on page 5-21

Overview

A packet switch is a component of a communication network that connects several

sources of data packets with several destinations. The switch directs each packet to the

correct destination, processing packets as they arrive. The switch must be able to manage

bottleneck situations in which several data packets have the same arrival time and the

same destination. Packet switches can use a variety of architectures and algorithms. This

section describes how to construct one particular packet switch model.

In this example, the goal is to construct a switch that:

• Connects three data sources to three destinations

• Holds arriving packets in a buffer (that is, a queue) for each of the data sources

• Randomly resolves contention if two or more simultaneous packets at the head of

their respective queues share the same intended destination, with no bias to any

particular source of packets

The example accommodates variable-length packets and assumes that packets from each

data source have exponential interarrival times.

The next figure shows an overview of the block diagram.

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MATLAB SIMEVENTS RELEASE NOTES Betriebsanweisung Seite 106