Lesson 3

• Computer network


  A system that connects two or more computing devices for transmitting and sharing information
• Computer networking


  • The branch of computer science that deals with the ideation, architecture, creation, maintenance, and security of computer networks
  • It is a combination of computer science, computer engineering, and telecommunication
• Computing devices


  Everything from a mobile phone to a server, connected using physical wires such as fiber optics or wirelessly
• Local area network (LAN)


  A small-scale network that revolves around one person or device, usually operating from one or two main devices, connecting just a few devices in a small, localized area
• Personal area network (PAN)


  Similar to LAN, transmits data within a small area, less secure and slightly weaker, provides users with the flexibility to use their devices in various locations
• Wireless local area network (WLAN)


  Used in educational environments, combine several independent networks into one cohesive unit
• Campus area network (CAN)


  A medium-sized network, larger than a LAN, combines several independent networks into one cohesive unit
• Metropolitan area network (MAN)


  A medium-sized network, larger than a CAN, costly but provides efficient connectivity between devices across a wide geographical range
• Wide area network (WAN)


  An extensive network that's not confined to geographical space, provides common network with far-reaching connectivity
• Storage area network (SAN)


  Stores mass amounts of sensitive data, centralizes data on a non-localized network that differs from the main operating one
• Passive optical local area network (POLAN)


  A low-cost network that can link various locations to one central network, providing the power to connect multiple entities to one hub
• Enterprise private network (EPN)


  An exclusive network that businesses build and operate to share company resources at high speeds, unique to a specific company, which ensures connection is secure
• Virtual private network (VPN)


  A private network that's available through the internet, similar to EPN, provides secure & private connection, both public and companies can use VPNs
• System-area network (SAN)


  A broad local network that provides connections in clusters, devices connected to a SAN operate as a single system, newly developing networks that operate at high speeds
• Intranet


  A set of networks that is maintained and controlled by a single entity, the most secure type of network, exists behind the router in a local area network
• Internet


  Also called internetwork, a collection of multiple networks connected by routers and layered by networking software, a global system that connects governments, researchers, corporates, the public, and individual computer networks
• Extranet


  Similar to intranet but with connections to particular external networks, generally used to share resources with partners, customers, or remote employees
• Darknet


  An overlay network that runs on the internet and can only be accessed by specialized software, uses unique customized communication protocols
• Network Topology


  • The physical or logical arrangement of devices and connections in a network, defines how devices are connected to each other and how data flows through the network

  
• Bus Topology


  Employs a single cable (Bus) to connect all the nodes, the main cable serves as the network's spine, all nodes are linked to the Taps and Drop Lines via the bus, data travels only in one direction and is removed by the terminator at the far end

  
• Ring Topology


  Devices are connected in a closed loop, with each device connected to two other devices, uses a token system where only nodes with tokens can transfer data
• Mesh Topology


  A network configuration in which computers are linked via various redundant connections, there are numerous routes from one computer to another, lacks a central point of communication

  
• Tree Topology


  Devices are connected in a hierarchical structure, with a central hub or switch at the top and sub-hubs or switches below it, data flows from top to bottom or bottom to top

  
• Star Topology


  All devices are connected to a central hub or switch, a hub connects all computers in this type of network topology
• Hybrid Topology


  A combination of two or more of the basic topologies, such as star-bus