This document provides an overview of the topics to be covered in a data communications and networking course. The course will cover network topologies, transmission modes, network models, signaling, encoding, multiplexing, error detection, data link protocols, LANs/WANs, internetworking, security, compression, TCP/IP, and application services. It defines key terms like data communication, networks, protocols, standards, and the Internet. The first two chapters will provide an introduction to the topics and discuss network models.

1. CIS 321 –
Data Communications &
Networking
Chapter 1 - Introduction

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321 Topics to be Covered
 Network Topologies &
Categories
 Transmission Modes
 Network Models
 Signaling and Media
 Encoding and Modulating
 High Speed Digital Access
 Multiplexing
 Error Detection and
Correction
 Data Link Control and
Protocols
 LANs/WANs,
VLANs/VPNs
 Frame Relay, ATM
 Internetworking
 Security
 Compression
 TCP/IP
 Application Services

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Part 1 Overview of Data
Communications and Networking
 Chapter 1
 Brief description of data communication, networking,
and protocol standards
 Chapter 2
 Network models

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Data Communication
 Why study data communications?
 Data communication – exchange of data between
two devices via a transmission medium
 Effectiveness depends on:
 Delivery, Accuracy, Timeliness

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Communication System Components

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Data Representation
 Text – represented as a bit pattern; codes often
used:
 ASCII; Extended ASCII; Unicode; ISO
 Numbers – represented by binary equivalent
 Images – bit patterns representing pixels
 Audio
 Video

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Direction of Data Flow
 Simplex – unidirectional; one transmits, other
receives
 Half-duplex – each can transmit/receive;
communication must alternate
 Full-duplex – both can transmit/receive
simultaneously

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Networks
 Set of devices (nodes) connected by media
 Distributed processing
 Advantages

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Network Criteria
 Performance – affected by # users, type of
medium, HW/SW
 Reliability – measured by freq of failure, recovery
time, catastrophe vulnerability
 Security – protection from unauthorized access,
viruses/worms

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Types of Connections
 Point-to-point –
dedicated
 Multipoint – shared

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Topology
 Physical or logical arrangement
 4 basic types: mesh, star, bus, ring
 May often see hybrid

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Mesh Topology
 Dedicated point-to-point
links to every other device
 Advantages
 Disadvantages

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Star Topology
 Dedicated point-to-point
links to central controller
(hub)
 Controller acts as
exchange
 Advantages
 Disadvantages

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Bus Topology
 Multipoint configuration
 One cable acts as a
backbone to link all
devices
 Advantages
 Disadvantages

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Ring Topology
 Dedicated point-to-point
configuration to neighbors
 Signal is passed from device
to device until it reaches
destination
 Each device functions as a
repeater
 Advantages
 Disadvantages

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Categories of Networks
 Based on size, ownership, distance covered, and
physical architecture
 Local Area Network (LAN) – smaller geographical
area
 Metropolitan Area Network (MAN) – network
extended over an entire city
 Wide Area Network (WAN) – large geographical area

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Internetworks
 Connection of two or more networks
 Internet vs. internet (notice case)

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The Internet
 Collaboration of more than hundreds of
thousands of interconnected networks
 1969 – started as ARPAnet, a small network of
connected computers
 1972 - Cerf and Khan – packet delivery and
Transmission Control Protocol (TCP)
 Shortly thereafter – evolution of TCP/IP
 A brief history of the Internet
 Internet Timeline

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Protocols and Standards
 Why do we need them?
 Protocol – set of rules that govern data
communication; defines what, how, and when
 Key elements – syntax, semantics, timing
 Standard – provides a model for development;
allows for interoperability

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Standards
 Types –
 De jure/Formal – legislated by an officially
recognized body
 De facto – by convention or widespread use
 Standards Organizations – committees, forums,
regulatory agencies
 Internet Standards
 Drafts
 RFC Process

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Summary
 Introduction to data communication, networking,
and protocol standards
 Next chapter…
 Network models

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Credits
 All figures obtained from publisher-provided
instructor downloads
Data Communications and Networking, 3rd edition by
Behrouz A. Forouzan. McGraw Hill Publishing, 2004