5.1 Networks

Question 1

What are Networks?

Answer 1

Networks are connections between nodes (devices) to share resources. Being connected to a network can be dangerous because there are more access points.

Question 2

What are the types of Networks?

Answer 2

1. Personal Area Network (PAN)
2. Local Area Network (LAN)
3. Wide Area Network (WAN)

Question 3

What is PAN?

Answer 3

A personal area network is within the range of an individual, +- 10m. Examples are:

1. Bluetooth

Question 4

What is LAN?

Answer 4

It is a network that connects devices close to one another, like in the same house; school; office.

Question 5

What is WAN?

Answer 5

A wide area network is a network over a broader, geographic area. For example, an internet connection is given by an ISP. The internet is a WAN made up of individual LANs.

Question 6

What is a Client-Server Network

Answer 6

In a Client-Server Network, every device is either Client or Server. A client will request resources from the server.

1. When a resource is wanted, the client establishes a connection with the server over the network
2. Servers backup and store data centrally, although expensive and difficult to run.
3. It is centralized

Question 7

What is a Peer-to-Peer Network

Answer 7

A P2P network is decentralized. Each node is equal in responsibility and can work as both client and server.

Question 8

What are the factors that affect Network Performance?

Answer 8

1. Latency
   
   1. The Delay, Speed of Signals
2. Bandwidth
   
   1. Max rate of Data Transfer (bps)
3. Error Rate
   
   1. How often data is corrupted
   2. How often data must be resent

Question 9

What are the differences between wired connections and wireless connections?

Answer 9

1. Wired connections are generally faster
   
   1. Though Bandwidths must be taken into account, but is shared across a network
2. Wireless range signals degrade quickly and can be blocked
3. Signals at the same frequency can interfere, leading to dara collisions
4. Bus topology have higher error rates

Question 10

What are network protocols?

Answer 10

They are rules that must be accepted to devices can be compatible and reliably communicate.

Question 11

How are protocols developed?

Answer 11

They are developed in layers, each responsible for a different part of the process of communication. Layers break the process down into managable self-contained parts.

1. Easier to develop because it is focused on one aspect
2. easier to develop standards
3. changing one layer won’t affect another

Question 12

What us the TCP/IP Protocol Stac?

Answer 12

It has 4 layers:

1. Application Layer
   
   1. HTTP/S; FTP; SMTP; IMAP & POP; DNS
2. Transport Layer
   
   1. TCP; UDP
3. Network Layer
   
   1. IP
4. Link Layer
   
   1. Ethernet; Wifi

Question 13

What is the Application Layer?

Answer 13

The application layer is where network applications can operate, e.g:

1. Web Browsers, Email Clients

Question 14

What is the Transport Layer?

Answer 14

This layer sets up communication between the two hosts, and includes the agreed rules.

Question 15

What is the Network Layer?

Answer 15

This layer addresses and packages data, and routes it.

Question 16

What is the Link Layer?

Answer 16

This is where the hardware and drivers operate.

Question 17

What is the Ethernet?

Answer 17

It is a standardised family of protocols.

1. Ethernet works at the link layer
2. it describes how devices on the same netwoek degment format data and transmit it

Question 18

What is Wi-Fi (WLAN)?

Answer 18

1. It is a form of wireless transmission, radio waves
2. EM waves are categorised on frequency
3. A channel represents a small frequency range, designated by number
4. Frequency overlap can cause interference.
5. Data is encrypted using WAP

Question 19

What is the TCP?

Answer 19

TCP is the transmission control protocol, which runs in the transport layer. It deals with the connection between devices, it:

1. receives data from the application layer
2. receives the packets from the network layer
3. splits data into packets
4. reassembles them
5. sends an acknowledgment

Question 20

What is the IP?

Answer 20

It is the internet protocol, it addresses packets with the source and destination’s IP address, and works at the network layer. The IP removes the IP addresses when the packets are no longer needed.

Question 21

What is HTTP?

Answer 21

It is the hypertext transfer protocol, a hypertext is a type of text with links. HTTPS is HTTP with encryption through certificates. HTTP is used to access a webpage from a web server, the process goes as:

1. The client requests a message
2. the webserver gives a response

Question 22

What is FTP?

Answer 22

The file transfer protocol is of the application layer, which handles file uploads and downloads. HTTP transfers viewable content whilst FTP transfers data.

Question 23

What are the email protocols?

Answer 23

1. SMTP
2. POP3
3. IMAP

Question 24

What are the outbound email protocols?

Answer 24

1. SMTP

Question 25

What are the Inbound email protocols?

Answer 25

1. POP3 2. IMAP

Question 26

What is SMTP?

Answer 26

The simple mail transfer protocol is of the application layer.. it handles outbound. It sends the email to a mail server, and then to the internet. SMTP servers have user databases.

Question 27

What is POP?

Answer 27

it is post office protocol, this is from the internet, mail server to the client. It doesn't keep client and server in sync. When the mail is downloaded, it is deleted from the server.

Question 28

What is IMAP?

Answer 28

It is internet message access protocol, where it keeps both client and server synced in which the mail is copied instead of downloaded. For the mail to be deleted from the server, you must contact the client.

Question 29

What are the network topologies?

Answer 29

Topologies are the arrangement of the nodes and connections in a network. 1. Bus 2. Star 3. Mesh 4. Ring

Question 30

What is the Bus Topology?

Answer 30

1. All clients, serbers and resrouces are connected to one medium, the bus. 2. When a node communicates, the data is transmitted down the bus. 3. All drivers receive it but only the intended recipient accepts and processes the message. 4. There are terminators on both ends, which are resistors. They prevent data from reverberating

Question 31

What are the advantages and disadvantages of the bus topology?

Answer 31

Advantages: 1. Cheaper, because less wires Disadvantages: 1. If the main bus fails, all fails 2. Prone to data collisions in high traffic, which slows the data down.

Question 32

What is the ring topology?

Answer 32

In this topology, each device is connected to two other devices, forming a ring for messages to travel around. The nodes take turns sending data, data is sent one direction through each device until the intended recipient receives it.

Question 33

What are the advantages and disadvantages of the ring topology?

Answer 33

Advantages: 1. Simple, less wires, cheaper. Disadvantages: 1. All nodes must be one for the data to be sent.

Question 34

What is the star topology?

Answer 34

Most home networks uses this topology, as each node is connected to the central connection point.

Question 35

What are the advantages and disadvantages of the star topology?

Answer 35

Advantages: 1. Data goes immediately to recipient Disadvantages: 1. If the central connection point fails, network stops.

Question 36

What is the mesh topology?

Answer 36

In a full mesh, every node is connected to every other node. In a partial mesh, there are simply many connections between nodes. A mesh could be used as a backup mechanism, called the redundancy as it is needed but used as an alternative route.

Question 37

What are the advantages and disadvantages the mesh topology?

Answer 37

Advantages: 1. Provides backup should one route fails 2. Direct links to recipient. Disadvantages: 1. Expensive, many wires 2. Complicated 3. Can't add one device without connecting to every other device.