Fundamentals of Computer Networks

Question 1

What are factors of a WAN?

Answer 1

• distributed ownership
• third - party carrier
• large geographical area

Question 2

What are the different headers that packets contain?

Answer 2

• The IP address it is going to
• The IP address it has come from
• Sequence number of packet
• Number of packets in the whole communication
• Error checking data

Question 3

What is a router?

Answer 3

Designed to route data packets across a WAN such as the Internet

Question 4

Define switch

Answer 4

A component of a LAN that knows the MAC addresses of each individual device connected to it locally

Question 5

What are the advantages of wireless networking?

Answer 5

• Users can move freely within the area of the network
• Users can share files and other resources connected to the network without needing a port
• Saves expense, time and inconvenience of needing to lay cables through the walls
• easier to add new devices as no new cabling is required
• instant transfer of data is much quicker

Question 6

What are the disadvantages of wireless networks ?

Answer 6

• File transfer speeds are generally slower with wireless connections
• Wireless connections can be obstructed by walls, ceilings and furniture
• Wireless networks are generally less secure and easier to hack into

Question 7

What are risks of wireless networks?

Answer 7

• Criminal activity ( unauthorised user can use wireless connections to hack into the network)
• Bandwidth stealing (intruders can slow things down)
• Confidentiality - If network information is not encrypted before transmission, an intruder can gain access to confidential information)

Question 8

What is a LAN?

Answer 8

Local Area Network usually covering a relatively smaller geographical area. Usually owned and managed by a single person or organisation

Question 9

Benefits of Networking Computers?

Answer 9

Sharing resources

• Folders/ files can be stored on a file server (accessed by authorised users from any computer on the network)
• Peripheral devices such as printers and scanners can be shared
• Internet connection an be shared and anu authorised user on the network can use email

Centralised Management

• User profiles and security can all be managed centrally
• Software can be distributed across the network rather than having to install it on each individual computer
• All files can be backed up centrally

Question 10

Disadvantages of networking computers ?

Answer 10

• If a file server goes down, no one can access their files or do any work
• Network faults could lead to a loss of data
• As network traffic increases, performance degrades so accessing resources might be slow
• It is difficult to make system secure from hackers
• Viruses may be able to infiltrate the network and infect every computer
• The larger the network becomes, the more difficult it is to manage

Question 11

What are the 2 different types of topologies ?

Answer 11

Star and bus

Question 12

Advantages of star topology?

Answer 12

• If one cable fails the other workstations are not affected
• Consistent performance even wen the network is heavily used
• Good security as data is received only by the node for which it is intended

Question 13

Disadvantages of star topology?

Answer 13

• Can be costly to install because there is a lot of cabling and extra hardware such as the switch
• If server or central switch fails then the whole network goes down

Question 14

Advantages of bus topology?

Answer 14

• Easy and inexpensive to install (less cabling that in a star topology)
• No reliance on a central node

Question 15

What is a PAN?

Answer 15

Personal Area Network, can be used for communication between devices themselves or for connecting to the Internet (Bluetooth).

Question 16

Disadvantages of bus topology?

Answer 16

• If the main cable fails then the whole network goes down
• Cable failures are hard to isolate because all of the computers in the network are affected
• Performance slows down as the amount of traffic increases
• Low security as every node can see all transmissions

Question 17

What are the 4 different methods of keeping a network secure?

Answer 17

1. Authentication
2. Encryption
3. Firewall
4. MAC address filtering

Question 18

Describe the different methods of authentication.

Answer 18

Password Protection - easiest way to stop unauthorised access to your computer or your files is to use a combination of a username and password

User access levels - are set for disks, folders and files so users can only access what they need to

Question 19

Describe encryption

Answer 19

Used to protect data and prevent it being hacked or accessed illegally, converts plaintext into ciphertext

Question 20

Describe Firewall

Answer 20

Prevent unwanted Internet traffic from gaining access to the LAN. Unauthorised users external to the network are blocked by the firewall, which can also block any attempts to gain access via certain ports used for restricted data transmission (FTP).

Question 21

Describe MAC address filtering

Answer 21

Every computer has a different MAC address therefore it is possible to use MAC filtering on a wireless network to determine which devices are allowed access to the network.

Question 22

Define protocol.

Answer 22

Set of rules that define how devices communicate.

Question 23

Specification and Examples of protocols

Answer 23

• format of data packets
• addressing system
• transmission speed
• error-checking procedures being used

Question 24

What is WAP?

Answer 24

Wireless Access Point, receives data from a a networks via its physical connection. Transmitter then converts this data into radio waves which are then transmitted.

Question 25

What are the different Protocols?

Answer 25

1. TCP/IP
2. UDP
3. HTTP
4. HTTPS
5. FTP
6. IMAP
7. SMTP

Question 26

Function of TCP/IP protocol?

Answer 26

TCP is a standard that defines how messages are broken up into packets and reassembles at the destination, IP protocol identifies the location of a device on the Internet and routes individual packets from source to destination.

Question 27

Function of UDP?

Answer 27

uses simple connectionless transmission model. Alternative to TCP but has no error-checking or correction.

Question 28

Function of HTTP and HTTPS?

Answer 28

HTTP accesses and receives web pages in form of HTML file on Internet, requests web server to transmit requested web page to the user’s browser for viewing. HTTPS is same but encrypts info so it cannot be understood if hacked.

Question 29

Function of FTP?

Answer 29

Standard network protocol used when transferring computer files between a client and server on a computer network.

Question 30

Function of IMAP?

Answer 30

An email protocol that stores email messages on a server but allows users to view and manipulate the messages as though they were stored locally on their own computers.

Question 31

Function of SMTP?

Answer 31

Protocol for sending e-mail messages between servers.

Question 32

What are the 4 different layers and the protocols in each layer?

Answer 32

Application layer - where network applications operate (HTTP, HTTPS, FTP, IMAP, SMTP)

Transport Layer - which sets up the communication between the two hosts and establishes settings such as ‘language’ and size of packets. (TCP and UDP)

Network/ Internet Layer - which addresses and packages data for transmission, and routes the packets across the network. (IP)

Link Layer - which is where network hardware such as NIC is located.