LAN basics

McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004

Chapter 1

Introduction


1.1 Data Communication

Components

Data Representation

Direction of Data Flow


Figure 1.1 Five components of data communication


Figure 1.2 Simplex


Figure 1.3 Half-duplex


Figure 1.4 Full-duplex


1.2 Networks

Distributed Processing

Network Criteria

Physical Structures

Categories of Networks


Figure 1.5 Point-to-point connection


Figure 1.6 Multipoint connection


Figure 1.7 Categories of topology


Figure 1.8 Fully connected mesh topology (for five devices)


Figure 1.9 Star topology


Figure 1.10 Bus topology


Figure 1.11 Ring topology


Figure 1.12 Categories of networks


Figure 1.13 LAN


Figure 1.13 LAN (Continued)


Figure 1.14 MAN


Figure 1.15 WAN


1.3 The Internet1.3 The Internet

A Brief History

The Internet Today


Figure 1.16 Internet today


1.4 Protocols and Standards1.4 Protocols and Standards

Protocols

Standards

Standards Organizations

Internet Standards


4.4 Transmission Mode4.4 Transmission Mode

Parallel Transmission

Serial Transmission


Figure 4.24 Data transmission


Figure 4.25 Parallel transmission


Figure 4.26 Serial transmission


In asynchronous transmission, we In asynchronous transmission, we send 1 start bit (0) at the beginning send 1 start bit (0) at the beginning

and 1 or more stop bits (1s) at the end and 1 or more stop bits (1s) at the end of each byte. There may be a gap of each byte. There may be a gap

between each byte.between each byte.

Note:Note:


Asynchronous here means Asynchronous here means “asynchronous at the byte level,” but “asynchronous at the byte level,” but the bits are still synchronized; their the bits are still synchronized; their

durations are the same.durations are the same.

Note:Note:


Figure 4.27 Asynchronous transmission


In synchronous transmission, In synchronous transmission, we send bits one after another without we send bits one after another without

start/stop bits or gaps. start/stop bits or gaps. It is the responsibility of the receiver to It is the responsibility of the receiver to

group the bits.group the bits.

Note:Note:


Figure 4.28 Synchronous transmission

Engineering

LAN basics