Week 2

Question 1

What is a Computer Network?

Answer 1

– A communications system
– Connects computers and peripheral devices
– Enables data/information transfer
– Improves internal communication
– Share resources

Question 2

What are Resources?

Answer 2

– Servers, Processing, Storage (hardware)
– Applications, data, files (software)
– Peripherals (e.g. printers, DVD burners, etc.)
(hardware)

Question 3

Components of a Computer Network: Media

Answer 3

– Twisted-pair wire
– Co-axial cable
– Fibre-optic cable
– Wireless
* Radio, Microwave,
Satellite

Question 4

Components of a Computer Network: Hardware

Answer 4

– Computer
– Peripheral
– Network card
– Router
– Modem

Question 5

Components of a Computer Network: Software

Answer 5

– Network OS
– Utilities
– Drivers
– Applications

Question 6

Components of a Computer Network: Network Design and Protocols

Answer 6

• Network Design
  – Type of network
  – Topology
• Protocols
  – Standards used

Question 7

Twisted-Pair Wire

Answer 7

– Ordinary telephone wire
– Copper wire is twisted into pairs

Question 8

Co-axial Cable

Answer 8

– Sturdy copper or aluminium wire
wrapped with spacers to insulate
and protect it
- Co-axial cable was traditionally used for TV and is still used for cable TV networks
which also carry digital data

Question 9

Fibre-Optic Cable

Answer 9

– One or more hair-thin filaments of
glass fibre wrapped in a protective
jacket.
- Fibre-Optic does not carry an electrical signal and uses light, which can potentially
carry an enormous amount of data. However, fibre optics cannot be easily connected
to individual machines which require a traditional cable or wireless connection.

Question 10

Disadvantages of Wireless

Answer 10

– Generally slower than wired connections
– Subject to interference
– Subject to congestion
– Easier to intercept
– So inferior to wired networks

Question 11

LAN (Local Area Network)

Answer 11

– Serves users within a limited geographical area
(normally ~2 Km) e.g. Belfield
Connects computers in a limited physical area
– Office, classroom, or building

Question 12

MAN (Metropolitan Area Network)

Answer 12

Covers a geographic area the size of a city or
suburb.

Question 13

WAN (Wide Area Network)

Answer 13

Covers a wide geographical area, such as a state or
a country

Question 14

VPN (Virtual Private Network)

Answer 14

Used by organisations to establish secure intranets
and extranets

Question 15

Client/Server Model

Answer 15

Workstation users
(clients) share
services of a
centralised computer,
called a server.

Question 16

Peer-to-Peer model

Answer 16

Computers share
equally with each
other, without using a
central server
Peer to peer connected machines with an equal role, it is useful for a small number of
machines in a small office or household.

Question 17

Pros/Cons of Client/Server

Answer 17

• Pros
  – Very secure OS
  – Better performance
  – Central servers easier to
  manage
  – Centralised back-ups
  – High reliability
• Cons
  – Expensive administration
  – More hardware intensive

Question 18

Pros/Cons of Peer-to-Peer

Answer 18

• Pros
  – Uses less expensive
  networks
  – Easy to administer
  – Contain both network OS
  and application SW
  – Ideal for small businesses
  and home users
• Cons
  – Individual user
  performance easily
  affected
  – Not very secure
  – Hard to back up

Question 19

Network Architecture

Answer 19

– Set of standard protocols, hardware, software, and
interfaces between end users and computers
– promotes an open, simple, flexible, and efficient
telecommunications environment

Question 20

Protocol

Answer 20

– A standard set of rules and procedures for the
control of communications in a network
– The best known protocol is Transmission Control
Protocol/Internet Protocol (TCP/IP) used for the
Internet
* Allows standard

Question 21

Real Fibre FTTH

Answer 21

• FTTH (Fibre to the Home)
  FTTP ( to premises)
• Now in Ireland
  – New estates
  – Some rural areas (Eir)
  – Some towns (ESB Siro)
  – Up to 1Gb/sec
• Very uneven coverage so far.
  – National Broadband and Project Stratum in NI to
  cover remote areas with government support.