Unit 3 Communication

Unit 3 communication for Computer Science

Networks

Networks

A collection of computer devices connected together.

Advantages and Disadvantages of network

The benefits of having a network, including shared hardware, software, and data; easier internal communication; centralized backup; easier network activity monitoring; and access to data from any computer.

The drawbacks of having a network, such as the need for a network manager, security issues, dependency on the server, and high initial cost.

LAN (Local Area Network)

A network where all computer systems are connected relatively close to each other, like within the same building or school.

WAN (Wide Area Network)

A network where all computer systems are located relatively far from each other, such as in different buildings or countries.

PAN (Personal Area Network)

A network where all computer systems are connected close to the user, like within the same house.

Network Topologies

The different ways in which the connections of a network are arranged.

Bus Network

A network topology where all devices are connected to a single cable.

Ring Network

A network topology where devices are connected in a circular manner.

Star Network

A network topology where devices are connected to a central hub or switch.

Switching

The ways in which data travels around networks, including circuit switching and packet switching.

Circuit Switching

Provides a dedicated link between two workstation, with no other data transmission possible while the connection is open.

Packet Switching

Data is split into small packets, each carrying the address of its destination, and can take alternate routes to reach the destination.

MAC Address (Media Access Control Address)

A 12 digit hexagon decimal number assign to each device connected to network

IP Address

The address of a network device on an IP network.

Advantages and Disadvantages of Bus Network

Advantages

• Easy to setup and add more workstation

• Quick to set up

• Cost-effective

Disadvantages

Difficult to troubleshoot

Limited cable length and number of workstation

Problem with the cable, all workstation goes down

Low security

Data collisions

Advantages and Disadvantages of Ring Network

Advantages

• Quick Data transfer

• Simple data transmission

• Little to no data collision

• Can add additional workstation

Disadvantages

• If one workstation fails, the whole network is broken

• Problem with the main cable or connection, the whole network goes down

• Difficult to troubleshoot

• To add additional workstation need to shut down the entire network

Advantages and Disadvantages of Star Network

Advantages

• Fast network speed

• Easy to setup

• Able to add more workstation without shutting down the entire network

• Any non-centralised fail will have very little effect on the network

• Minimal network collision

• Better security

Disadvantages

• Expensive to install

• Switch/hub is needed

Advantages and Disadvantages of Circuit Switching

Advantages

• Reliable

• Once it is setup, it is fast and usually error free

Disadvantages

• Take time to establish connection

• If anywhere fails, the whole connection fails

Advantages and Disadvantages of Packet Switching

Advantages

• Do not need a dedicated line

• Can take alternate route

• Tends to error free

• High efficiency as if one packet fails to send, you only need to resend that packet

Disadvantages

• May arrive in wrong order

• May cause a delay until all packets are sent

• Large memory is needed to hold the packets

Describe TCP

TCP stand for transmission control protocol and it is a protocol that allows packets to be send and received between computer system

Describe HTTP

A protocol used to transferred multi-media webpage over the internet

Describe FTP

A protocol used to copying a file from one location to other via a network or internet

Describe the 5 layer of TCP

1. Physical layer

   • Transmit raw data

2. Data link layer

   • It send data from network layer to physical layer

3. Network layer

   • Addressing and routing data

4. Transport layer

   • Ensures data is transferred from one point to another with errors

5. Application layers

   • Provides interface to the software

What is IMAP

Internet messaging access protocol is a protocol that stores email message in a mail server

What is POP3

Post office protocol 3, it receives emails for a client and stores it on a mail server

Describe SMTP

Simple Mail transfer protocol, uses to deliver mail to the server