Network Theory
Data Communication
Definition
- Exchange of data between 2 devices via some form of transmission medium
- Fundamental characteristics of effective data communication
- Delivery: Delivering data to the correct destination
- Accuracy: Delivering data without alteration in the start and end points
- Timeliness: Delivering data in a timely manner
- Jitter: Delivering data with minimal variation in packet arrival time
Components
- Message: The information or data to be communicated
- Sender: The device that sends the data message
- Receiver:** **The device that receives the message
- Transmission Medium: The physical path where a message travels
- Protocol: A set of rules that govern data communication, representing an agreement between the sender and communicating devices
Networks
Definition
- Two or more devices connected together for the purpose of communication
- A device that is not connected to a network is a stand-alone
- A device can be a host or a connecting device
Advantages
- **File Sharing: **Users can share files with others
- **Hardware Sharing: **Users can share the use of hardware
- **Communication: **Users can communicate information
- **Roaming Access: **Users can access their data with any device on the network
- **Centralised Maintenance and Updates: **Apply software updates across a network
- **Centralised Security: **Implementation of antivirus and firewalls across a network
- **User Monitoring: **Monitor user action across a network
- **Different Access Levels: **Users can have different access rights
Disadvantages
- Cost: Hardware costs
- Additional resources to manage network
- Spread of malware and hacking: Viruses and malware can spread
Types of Networks
Local Area Network (LAN)
- Geographically confined to one building or site
Wide Area Network (WAN)
- Network spread over a wide geographical area
Internetwork / internet (lowercase)
- 2 or more networks (LAN or WAN) are connected
Internet
- Global system of interconnected computer networks that use the internet protocol suite (TCP/IP) to communicate between networks and devices
Intranet
- Private computer network used within an organisation to facilitate communication, collaboration and access to company resources
- Restricted to authorised users within the organisation