Transcript Chapter 1 Data Communications and Networks Overview

Introduction to Networking
Lesson 01
NETS2150/2850
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A Communications Model
Source
generates data to be transmitted
Transmitter
Converts data into transmittable signals
Transmission System
Carries data
Receiver
Converts received signal into data
Destination
Takes incoming data
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Simplified Communications
Model - Diagram
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What’s the Internet?
millions of connected
computing devices: hosts,
end-systems
PCs workstations, servers
PDAs, phones
router
server
workstation
mobile
local ISP
running network apps
communication links
regional ISP
fiber, copper, radio, satellite
routers: forward packets
(chunks of data)
enterprise
network
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Types of Networks
Various categorisation of networks
One way - geographical span
Categories of Networks:
Local Area Network (LAN)
Metropolitan Area Network (MAN)
Wide Area Network (WAN)
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Local Area Networks
Smallest scope
Building or small campus
Below 10 km
Usually owned by same organization as
attached devices
Much higher capacities
Usually broadcast systems
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Typical LAN Configurations
Switched LANs
Switched Ethernet (802.3)
• May be single or multiple switches
Asynchronous Transfer Mode (ATM) LAN
Wireless (802.11)
Supports mobility
Ease of installation
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Metropolitan Area Networks
(MAN)
Middle ground between LAN and WAN
Private or public network
High speed
Large area
10 – 100 km
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Wide Area Networks
Large geographical area, > 100 km
Crossing public rights of way
Rely in part on public (ISP) network
Alternative technologies
Circuit switching
Packet switching
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Circuit Switching
Dedicated communications path
(physical) established for the duration
of the conversation
E.g. telephone network
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Packet Switching
Data sent out of sequence
Small chunks (packets) of data at a
time
Packets passed from node to node
between source and destination
Used for computer to computer
communications
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Summary
Communications Model
Network classification based on
geographical span
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