Introduction to Networks

Note by Liam-Beckwith, updated more than 1 year ago More Less
Created by Liam-Beckwith over 3 years ago


This set of notes will define exactly what a network is. Highlight Communication Networks and different varieties. I will then finish off with some discussion to Circuit Switching networks.

Resource summary

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What is a Network?"A large system consisting of many similar parts connected together to allow movement or communication between or along the parts."A network is a group of two or more computer systems linked together. There are many types of computer networks, including the following:Local-Area Networks (LANs): The computers are geographically close together (within the same building).Wide-Area Networks (WANs): The computers are farther apart and are connected by telephone lines or radio waves.Campus-Area Networks (CANs): The computers are within a limited geographical area, such as a campus or military base.Metropolitan-Area Networks (MANs): A data network designed for a town or city.Home-Area Networks (HANs): A network contained within a user's home that connects a person's digital devices.

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Communication NetworksWhat was the first communication network? It was in fact the Postal Service, typically through carrier pigeons in the First World War. Telephone Networks also existed around this time and an interesting fact is that before telephone networks even existed, phones were connected point-to-point. People needed a telephone for each person they wanted to speak to, so if an individual had six contacts, they would need six telephones. They would whistle until the other person answered.Telephone exchanges were later implemented through a Public Switched Telephone Network (PTSN). This is the international telephone system based on copper wires carrying analog voice data. This is in contrast to newer telephone networks base on digital technologies, such as Integrated Services Digital Network (ISDN) or Fibre Distributed Data Interface (FDDI).

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Computer NetworkA computer network is a collection of numerous devices including: Computers Switches Routers Bridges Cables Wi-Fi Routers/Access Points The Internet is one of the most common networks we know of today. This is very different from the World Wide Web (WWW). However, the Internet was started in the 1960's with the formation of ARPAnet. More on this later.

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CommunicationThe primary purpose of a computer network is to communicate information from one point to another, in a efficient, quick and reliable way.However, there are many ways in which a computer ways can be configured.

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ARPAnetThe Advanced Research Projects Agency Network (ARPAnet) was the worlds first packet switching network and the first network to use the Transmission Control Protocol/Internet Protocol (TCP/IP) back in 1969.It was created as an experiment by the US military to test communications in the event of a nuclear strike during the Cold War.It was later used to connect universities and research centres across the USA before growing exponentially. The first two nodes that formed the ARPAnet was UCLA and the Standard Research Institute (University of Utah).

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Connected DevicesA new computing concept which is becoming ever more popular is the Internet of Things (IoT). This describes a future where everyday physical objects will be connected to the Internet and be able to identify themselves to other devices. This is closely identified with Radio-Frequency Identification (RFID) which is the use of electromagnetic fields to automatically identify and track tags attached to objects. However, this also includes other sensor technologies, wireless technologies or QR codes.The IoT is significant due to how an object can represent itself digitally, making it greater as a result. The object no longer relates to just one individual, but is now connect to surrounding objects and database data. When many objects act in unison, they are known as having "ambient intelligence."We can also look at the amount of devices which are currently connected to the Internet. We recently passed through the barrier in which there are more devices connected to the Internet than there are people on the planet. This figure is going to continue to rise in the future, which proves to be a very exciting prospect.

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Circuit-SwitchingA circuit-switching network is a type of communication medium in which a dedicated channel or circuit is established for the duration of a transmission with full bandwidth.This results in minimal delays and is ideal for communications that require data to be transmitted in real time. However, this is highly inefficient compared to packet-switching networks if some amount of delay is acceptable.Just remember that circuit-switching networks are sometimes called connection-oriented networks. However, that although packet-switching is essentially connectionless, a packet-switching network can be made connection-oriented by using a higher-level protocol. Transmission Control Protocol (TCP), for example, makes Internet Protocol (IP) networks connection-oriented.

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