A LAN (Local Area Network) is a computer network that connects devices within a limited area such as a home, school, or office building. It allows for the sharing of resources such as printers, files, and internet connections between devices on the network.

A LAN (Local Area Network) Administrator is responsible for managing and maintaining the local network infrastructure of an organization. Their duties include configuring and monitoring network devices, such as routers and switches, ensuring network security, troubleshooting network issues, managing user accounts and permissions, and implementing network upgrades and updates. They also oversee network backups and disaster recovery plans, as well as provide technical support to end-users. Additionally, they may be responsible for managing network-related projects and collaborating with other IT professionals to ensure the smooth operation of the organization's network.

A WAN (Wide Area Network) is a type of computer network that spans over a large geographical area, typically connecting multiple smaller networks such as LANs (Local Area Networks) or MANs (Metropolitan Area Networks). WANs are often used by businesses and organizations to connect their offices or branches located in different cities or countries.

A WAN Administrator specializes in network-oriented tasks, such as developing and programming scripts for network task automation and implementing software and hardware upgrades network-wide. Their duties are focused on maintaining and optimizing the WAN infrastructure, rather than user-oriented tasks. They must have specialized knowledge in their field to effectively manage and troubleshoot WAN issues. Overall, their role is critical in ensuring the WAN operates efficiently and effectively.

A PAN stands for Personal Area Network. It is a type of computer network that is used for communication among devices such as computers, smartphones, and tablets within a short range, typically within a few meters.

A CAN stands for Campus Area Network, which is a type of computer network that connects multiple buildings within a limited geographic area, such as a university campus or corporate headquarters.

A MAN (Metropolitan Area Network) is a computer network that spans a metropolitan area or a city. It typically covers a larger geographic area than a LAN (Local Area Network) but smaller than a WAN (Wide Area Network). MANs are often used by organizations to connect their offices located in different parts of a city or metropolitan area.

An Enterprise Network (EN) is a computer network that connects multiple devices and computers within an organization or company. It is designed to facilitate communication and data sharing among employees, departments, and locations. ENs typically include local area networks (LANs), wide area networks (WANs), and other networking technologies such as routers, switches, and firewalls. The goal of an EN is to provide a secure and reliable network infrastructure that supports the organization's business operations and objectives.

A Global Area Network (GAN) is a network that connects multiple local area networks (LANs) across a large geographic area, such as a country or the entire world. It allows for communication and data sharing between different LANs, and can be used by businesses, organizations, and governments to connect their offices and facilities across different locations.

The Internet is a global network of interconnected computers and servers that communicate with each other using standardized communication protocols. It is used for a wide range of purposes, including communication, information sharing, entertainment, e-commerce, and education.

An Intranet is a private network that is only accessible to an organization's members, employees, or others with authorized access. Its purpose is to facilitate communication, collaboration, and information sharing within the organization, while also providing a secure platform for storing and accessing sensitive data. Has same services and protocols as the internet.

An Extranet is a private network that allows authorized external users to access specific resources of a company or organization. Its purpose is to facilitate communication and collaboration between the company and its partners, customers, or suppliers, while maintaining security and control over the shared information.

A Segment in a network refers to a portion of a network that is separated by bridges, routers, or switches. It can be a physical or logical division of a network and is used to control the flow of network traffic. Segments can be used to improve network performance, security, and manageability.

A Network Model is a conceptual representation of how data flows within a network. It defines the structure of the network, the communication protocols used, and the methods of data transmission.

Types of Network Models: Centralized, Client/Server, Peer-to-Peer, Mixed Mode.

A Centralized Network Model is a type of network architecture where all communication between devices goes through a central node or server. This centralization allows for easier management and control of the network, but can also create a single point of failure.

In a Client/Server Network Model, multiple clients connect to a central server to access resources such as files, printers, and applications. The server manages and controls access to these resources, while the clients make requests for them. This model allows for centralized management and security, as well as efficient use of resources.

A Peer-to-Peer Network Model is a type of network where each node in the network can act as both a client and a server, allowing for decentralized sharing of resources and information between all nodes without the need for a central server.

A Mixed Mode Network Model in computer networks is a combination of different network architectures such as peer-to-peer, client/server, and centralized models. This allows for greater flexibility and customization in network design to meet specific needs and requirements.