Networks - paper 1

Question 1

What is the definition of a network?

Answer 1

A name given to two or more computers connected that can transmit data between each other.

Question 2

What are the two types of network topology?

Answer 2

Physical topology
Logical topology

Question 3

What is a physical topology?

Answer 3

The physical layout of wires and components which form the network

Question 4

What is a logical topology?

Answer 4

The layout that shows how data flows

Question 5

What are the features of a bus topology and what are its advantages/disadvantages?

Answer 5

All devices are connected to a backbone cable that is connected to a terminator
Advantages:
Relatively inexpensive
Doesn’t require any additional hardware.
Disadvantages:
If the backbone cable fails the entire network fails
As traffic increases, performance decreases
All computers can see the data transmission

Question 6

What are the features of a star topology and what are its advantages/disadvantages?

Answer 6

Uses a central node (often a switch) to direct data through the network.
MAC addresses are used to uniquely identify each device
Advantages:
Performance is consistent even with heavy network traffic
If one cable fails only that terminal is affected
Transmits data faster, giving better performance than bus
Easy to add new stations
No data collisions
Disadvantages:
Expensive due to the switch and cabling
If the central switch fails, all the network fails

Question 7

What are the features of a physical mesh topology and what are its advantages/disadvantages?

Answer 7

Every node is connected to every node, can either use wires or wifi
Advantages:
If using WIFI there is no wire costs
AS number of nodes increases reliability and speed of network becomes better
Nodes are automatically incorporated
Nodes don’t go through a central switch improving speed
Disadvantages:
If using a wireless network, devices have to be able to have wireless capability
If using a wired network a large quantity of cable is required
Maintaining the network is difficult

Question 8

What is a protocol?

Answer 8

A set of rules defining how two computers communicate with each other.

Question 9

What are 4 protocols and what are they used for?

Answer 9

HTTP - used for web page rendering
TCP/IP - A networking protocol used for the routing of packets through networks
POP3/ IMAP - used for emails
FTP - used for the transmission of files over networks

Question 10

What are the layers of the TCP/IP stack?

Answer 10

Application layer
Transport layer
Internet layer
Link layer
ATIL

Question 11

What happens in the application layer?

Answer 11

Decides which protocol to use

Question 12

What happens in the transport layer?

Answer 12

Establishes the end to end connection
Splits up data into packets
If any packets aren’t received this layer requests them again

Question 13

What happens at the internet layer?

Answer 13

Adds the source and destinations IP addresses

Question 14

What happens in the link layer?

Answer 14

The actual connection between network devices
Adds MAC address
Identifies the NIC of the source and destination computers

Question 15

What is the DNS?

Answer 15

The Domain Name System is the system used to name and organise internet resources.
It is a hierarchy in which the TLD is at the top and goes down in layers to 2LD, 3LD, 4LD

Question 16

Why is the DNS used?

Answer 16

Domain names are much easier to remember than IP addresses.

Question 17

What does the DNS server do?

Answer 17

Translates the address we type in to our search bar to its corresponding IP address.

Question 18

What is in each layer of a packet?

Answer 18

Header:
Sender and recipient IP address
Protocol being used
Order of packets
Time to live - so it doesn’t infinitely travel
Payload:
The data being sent
Trailer:
Checksum or redundancy check

Question 19

What are the two ways to exchange data?

Answer 19

Packet switching, circuit switching

Question 20

What is packet switching and what is its advantages/disadvantages?

Answer 20

Data is communicated using packets across a network
Advantages:
Multiple methods to ensure data arrives intact
Multiple routes the packets can take so if one is broken not a problem
Packets can be transferred over every large network
Disadvantages:
Time is spend deconstructing and reconstructing packets
Must wait for all packets to arrive before data can be recieved

Question 21

What is circuit switching and what are its advantages/disadvantages?

Answer 21

A method of communication where a direct link is created between two devices, the link is maintained for the duration of the entire conversation.
Advantages:
Data arrives in a logical order which results in a quicker reconstruction of the data
Enables two user to hold a call without delay in speech
Disadvantages:
Bandwidth is wasted when there is no data being sent
Devices must transfer and receive data at the same rate
Using switched means electrical interference may be produced which can damage or destroy data
No other users can use that part of the network while the transmission is ongoing.

Question 22

What is a client server network and what are its advantages/disadvantages?

Answer 22

Terminals that are known as clients connected to a server. The server is a powerful central computer that is stronger than a terminal.
Advantages:
More secure data as all in one location
Central backups are carried out
Data and resources can be shared between clients
Disadvantages:
Relatively expensive to set up
If server doesn’t work - nothing does
Trained staff are required to maintain the server

Question 23

What is a peer to peer network and what are its advantages/disadvantages?

Answer 23

A network in which computers are connected to each other so that they can share files.
Advantages:
Cheaper to set up
Allows users to share recourses
Easy to maintain
Not dependant on a central server
Specialist staff not required
Disadvantages:
Impossible to trace the origin of files
Backups must be performed separately
Poorer security
May be difficult to locate resources.