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Overview of Overview of Data Communications Data Communications

and and NetworkingNetworking

PART IPART I

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Overview

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Chapters

Chapter 1 Introduction

Chapter 2 Network Models

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Chapter 1

Introduction

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1.1 Data Communication

Components

Data Representation

Direction of Data Flow

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Figure 1.1 Five components of data communication

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Data Representation

Text: ASCII (7 bits), Unicode (32 bits)Numbers: Binary numbers (bit patterns)Images: Bit patterns: pixels,resolution,RGB,YCMAudio: Continuous signalVideo: Continous or discrete images

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Figure 1.2 Simplex

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Figure 1.3 Half-duplex

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Figure 1.4 Full-duplex

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1.2 Networks

Distributed Processing

Network Criteria

Physical Structures

Categories of Networks

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Figure 1.5 Point-to-point connection

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Figure 1.6 Multipoint connection

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Figure 1.7 Categories of topology

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Figure 1.8 Fully connected mesh topology (for five devices)

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Figure 1.9 Star topology

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Figure 1.10 Bus topology

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Figure 1.11 Ring topology

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Hybrid Networks

Some networks are a combination:

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Figure 1.12 Categories of networks

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Figure 1.13 LAN

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Figure 1.13 LAN (Continued)

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Figure 1.14 MAN

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Figure 1.15 WAN

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1.3 The Internet1.3 The Internet

A Brief History

The Internet Today

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History.. Internet with a capital I :) 1969: ARPA (Advanced Research Projects

Agency) of Department of Defense, USA 4 nodes: UCLA, UCSB,Stanford,Utah 1972: Vinc Cerf / Bob Kahn paper

“Internetting Project” - TCP mentioned Split IP and TCP (IP=Datagram routing,

TCP=segmentation,reassembly,error detection)

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Size of internet

Started with 4 computers.. :) 1.407 billion users > 1,000,000,000,000 URLs. (1 trillion) Seems to double every 5.5 years

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Figure 1.16 Internet today

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1.4 Protocols and Standards1.4 Protocols and Standards

Protocols

Standards

Standards Organizations

Internet Standards

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Protocols

Protocol: Set of rules that govern data communications.

Syntax: Structure of data Semantics: Meaning of each section of

bits. Timing: When can data be sent, and

How fast

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Standards De Facto: Not approved by an organized body.

QWERTY, AA battery De Jure: Standards legalized by an official body.

ISO: International Organization for Standardization ITU-T: International Telecomm Union (UN) ANSI: American National Standards Institute IEEE: Institute of Electrical and Electronics Engineers FCC: Federal Comm Commission (Radio/TV/comm)