1.3 Computer Networks

Question 1

What are standalone computers?

Answer 1

Computers that are not connected to any network

Question 2

What are the 5 advantages of networks?

Answer 2

• Users can share files
• Users can share peripherals (printers) and
  connections to other networks (internet)
• Users can access files on any computer within
  the network
• Servers can control security, software updates
  and back up of data
• Communication with other people, e.g. email
  and social networking.

Question 3

LAN

Answer 3

Covers a small geographical area

Question 4

LAN Properties

Answer 4

• All hardware used in the LAN is owned by an
  organisation

Question 5

WAN

Answer 5

Covers a large geographical area, connecting LANs together

Question 6

WAN properties

Answer 6

• Infrastructure between the LANs are hired
  from telecommunication companies who owns
  and manage it

Question 7

WAN connections

Answer 7

• Telephone lines
• Satelite links
• Fibre optic cables

Question 8

LAN connections

Answer 8

• UTC cable
• Fibre optic cable
• Wireless (WiFi)

Question 9

Computers in a LAN are connected with a _________?

Answer 9

switch

Question 10

Computers in a WAN are connected with a __________?

Answer 10

router

Question 11

Disadvantages of networks

Answer 11

• Increased security risks to data as its being
  shared
• Malware and viruses spread easily between
  computers
• If central server fails, all computers connected
  to it may not work
• Computer run more slowly if there is a lot of
  data travelling on the network

Question 12

What are the 5 factors that affect the performance of networks

Answer 12

• Bandwidth
• Number of users
• latency
• error rate
• Transmission media

Question 13

Bandwidth

Answer 13

The amount of data that can be sent and received in a given time.
- measured in bit per second (bit rate)

Question 14

Number of users

Answer 14

Too many users or devices can cause the network to slow down if there is insufficient bandwidth for the data

Question 15

Transmission Media

Answer 15

• Wired connection has a higher bandwidth than
  wireless
• Fibre optic cables has a higher bandwidth than
  copper

Question 16

Error rate

Answer 16

dependent on the range of devices from the WAP and other environmental factors.

Question 17

What is it called if a network uses a server

Answer 17

Client server

Question 18

What is it called if a network does not use a server

Answer 18

Peer to Peer network

Question 19

Client server 3 advantages

Answer 19

• Easier to manage security files
• Easier to take backups of all shared data
• Easier to install software updates to all
  computers

Question 20

Client Server 3 disadvantages

Answer 20

• Can be expensive to set up and maintain
• Need an IT specialist to maintain
• Server is a single point of failure

Question 21

Peer-to-Peer 5 Advantages

Answer 21

• Very easy to maintain
• Specialist staff are not required
• no dependency on a single computer
• cheaper to set up
• No expensive hardware required

Question 22

Peer-to-Peer 3 Disadvantages

Answer 22

• Network less secure
• Users need to managed own backups
• Difficult to maintain a well ordered file store

Question 23

LAN hardware

Answer 23

• NIC (Network Interface Card)
• WAP (Wireless Access Point)
• Switch
• Router
• Copper cables
• Fibre optic cables

Question 24

Network Interface Card

Answer 24

Connects device to wired or wireless networking connection
- uses protocol to ensure successful
communication

Question 25

Wireless access point

Answer 25

Allows wireless devices to access the network - more convenient - less bandwidth than wired connections - Security is a problem

Question 26

Switch

Answer 26

Uses NIC address on a device to route traffic

Question 27

Router

Answer 27

Sends data between networks - uses IP address on a device to route traffic to other routers

Question 28

Internet

Answer 28

World wide collection of networks that use the internet protocol suite (TCP/IP)

Question 29

World Wide Web

Answer 29

Collection of webpages hosted on web servers - Uses HTTP

Question 30

IP address

Answer 30

Uniquely identifies a device connected on a network and defines where it is located geographically

Question 31

Domain Name Server

Answer 31

1. Web browser acts as a client and connects to a DNS server to check if whether the domain name is in its database 2. DNS server checks for the domain's IP address in its database. If it doesnt have it, it acts as a client and connects to other DNS servers until it finds it 3.When it has found the IP address, its returns to the original client so the user can connect to the website

Question 32

The cloud

Answer 32

The delivery of services over the internet

Question 33

The cloud advantages

Answer 33

- Services accessed anywhere - More efficient for the user (hardware managed externally) - Automatic updates - Better security - Large storage capacity

Question 34

The cloud disadvantages

Answer 34

- Need internet connection - Fully reliant on the host - may be costly for users

Question 35

Topology

Answer 35

A given arrangement of all the elements you need for networking

Question 36

Star network topology

Answer 36

All devices connected to the central switch - single point of failure

Question 37

Full mesh network

Answer 37

Every device is connected to every other device - if any connections break other pc wont be affected - A lot of cabling and switches = cost

Question 38

Partial mesh network

Answer 38

Multiple routes exist between devices but every device is not connected to every other device - Lowers the amount of hardware needed compared to full mesh

Question 39

Ethernet

Answer 39

Used for connection wired local area networks

Question 40

Encryption

Answer 40

Scrambling the data into cypher text using a 'master key' created from the SSID of the network and the password

Question 41

MAC adress

Answer 41

used to route frames on a local area network

Question 42

IP address

Answer 42

Used to route packets on a wide area network

Question 43

What are the 2 versions of IP address

Answer 43

IPv4 and IPv6

Question 44

IPv4

Answer 44

- written as 4 numbers - periods (.) - 32 bits

Question 45

IPv6

Answer 45

- Written as 8 groups - colons : -

Question 46

What are the 2 parts of IPv4

Answer 46

Network identifier (3 bytes) and Host identifier (1 bytes)

Question 47

What is a protocol

Answer 47

A set of instructions that allow two devices to communicate