Fundamentals of Information Technology - Chapter 17: Computer Networks PDF

# Fundamentals of Information Technology ## Chapter 17: COMPUTER NETWORKS ### Network Definition - A network is the interconnection of two or more systems. - The minimum number of systems needed to make a network is two. ### Computer Networks Types - Local Area Networks (LAN) - Metropolitan Area...

# Fundamentals of Information Technology ## Chapter 17: COMPUTER NETWORKS ### Network Definition - A network is the interconnection of two or more systems. - The minimum number of systems needed to make a network is two. ### Computer Networks Types - Local Area Networks (LAN) - Metropolitan Area Networks (MAN) - Wide Area Networks (WAN) ### Local Area Networks (LAN) - Networks that connect computers within a small distance (a room or building) are called LANs. - Multiple computers connected together can share data and peripherals like printers and modems. - This reduces hardware equipment cost. - Some applications of LANs include: - File transfer and access - Accessing the internet - Providing a Management Information System ### A Metropolitan Area Network - Metropolitan area networks use the distributed queue dual bus. - MAN is larger than a LAN and can cover areas as large as a city. - The distributed queue dual bus system uses two buses connected to all computers. ### A Wide Area Network - A WAN connects computers that are remotely placed. - It can connect across countries, continents, or the entire globe. ### Comparison of LAN, MAN, WAN | CRITERIA | LAN | MAN | WAN | |--------------------|------------|------------|------------| | Cost | Low | High | Higher | | Network Size | Small | Larger | Largest | | Speed | Fastest | Slower | Slowest | | Transmission Media Type | Twisted-pair | Twisted-pair and fibre-optic cables | Fibre optic, radio wave, and satellite | | Number of Computers | Smallest | Large | Largest | ### Network Topology - Different network topologies: - Star Topology - Ring Topology - Bus Topology - Mesh Topology - Tree Topology ### Network Topology Diagram - A diagram is presented depicting the five network topologies: - Star - Ring - Mesh - Bus - Tree ### Star Topology - The star topology uses a central computer to which all other computers are connected. - Computers in this topology cannot communicate directly. - One advantage is that a faulty node can be isolated without affecting the rest of the network. - The star topology is commonly used due to its good performance during moderate load. - However, it can have problems with high traffic, and two terminals cannot interact directly. - This leads to no privacy in the network since communication must flow through the central computer. - Another disadvantage is that if the central computer malfunctions, the entire network stops functioning. ### Ring Topology - In the ring topology, all computers are connected in a closed loop (shaped like a ring). - Data travels sequentially from one computer to another until reaching its destination. - There is no central computer in the ring topology. - Although the ring topology offers less privacy than the star topology, it offers better performance during heavy traffic. ### Bus Topology - The bus topology is referred to as the multipoint topology. - All nodes are connected to a bus that runs through the network. - Each computer has a unique address. - Data is transmitted over the bus and includes the destination address. - Only the computer with the correct address accepts the data. - The bus supports two-way data transmission. ### The Mesh Topology - The mesh topology requires every computer to be connected to every other computer within the network. - This requires a significant number of interfaces, making installation complex. - The length of cable used is also significant. - The mesh topology offers faster data transfer than other topologies discussed. - It is also fault-tolerant as data can be routed over alternate paths if one path fails. ### Tree Topology - The tree topology connects computers hierarchically. - Data transmission is relatively slow. - The tree topology's success relies on a central computer, just like the star topology. - Failure of the central computer leads to the failure of the entire network. ### Transmission Technology - **Broadcast:** Transmits data to all devices on the network, essentially one-to-all communication. - **Multicast:** Transmits data to multiple receivers simultaneously, usually for video streams or data for groups. - **Unicast:** Transmits data one-to-one from one device to another using a specific IP address. ### Real-World Applications - Unicast, multicast, and broadcast are used in many applications. - Multicast is used in video and audio distribution, sending data to many receivers, as well as in online gaming where data is sent to specific groups. - Unicast is used for one-to-one communication. - Broadcast is used to transmit data to all devices on the same network, such as in television networks.