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Understanding computer networks

Computer networks overview

A network is a collection of two or more interconnected devices that use a common language or protocol to exchange information. The network has a series of points known as nodes that are interconnected by communication paths.

Most people are familiar with home computer networks that connect two computers to the internet. They also consist of more complex applications that connect all computers, servers and mobile devices for multinational corporations all over the world.

Just like computer networks, electrical equipment uses communication networks to connect and control equipment as well as gather and transfer data.

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Networking applications

A network can be as simple as connecting a monitoring device to a single computer or as complex as sending information around the world via the internet through a series of different communication devices and protocols. 

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Residential

Residential applications such as a single-family home can be networked by using structured wiring to manage voice, data and video.

You can connect your computer, security system, television, telephone, audio and more via the ethernet to a centralized system that lets you control access and configuration.

For example, you can link your outdoor security camera to your television so you can see who's ringing your doorbell. 

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Commercial

Examples of commercial facilities requiring networking include: 

  • Shopping malls 
  • Educational facilities 
  • Sports venues 
  • Entertainment complexes 

A communications network allows the facility manager to control panelboards and optimize sunlight and indoor lighting (daylight harvesting) as well as program the building management systems to reduce lighting output on holidays and evenings. 

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Industrial

Industrial applications use communications networks to optimize power usage and control manufacturing processes. Examples include: 

  • Refinery 
  • Automotive assembly 
  • Water treatment 

A water/wastewater plant uses power metering to measure overall power usage, and process control is applied to synchronize the pumping operation.

Benefits of a communication network

A communication network in power management or industrial automation system: 

  • Ensures power is available and used efficiently 
  • Minimizes damage to electrical equipment 
  • Improves reliability and safety in industrial, commercial and residential applications
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Characteristics of a communication network

  1. Type of signal
    Voice, data, voice and data

  2. Who can use the network
    Public, private 

  3. The nature of its connection
    Wired, wireless 

  4. The types of physical links
    Fiber optic, coaxial cable, category 5 (Cat 5), copper wire 
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Types of communication networks

A communication network is defined by its scope or scale. A network is any collection of independent computers or electrical equipment that exchanges information with each other over a shared communication medium.

Common types of networks are:

  • Local Area Network (LAN)
  • Metropolitan Area Network (MAN)
  • Wide Area Network (WAN)
  • Wireless Local Area Network (WLAN)

Local Area Networks

Local Area Networks (LANs) are usually confined to a limited geographical area such as a single building or corporate campus. LANs can be small, linking as few as three computers, but often can link hundreds of computers used by thousands of people. 

The worldwide proliferation of LANs throughout business and education organizations is due to the development of standard networking protocols and media. The most widely used LAN connectivity technology is ethernet.

Ethernet

Ethernet is the most popular physical layer LAN technology in use today. It defines the number of conductors required for a connection, the expected performance thresholds, and provides the framework for data transmission.  

Ethernet is popular because it strikes a strong balance between speed, cost and ease of installation. These benefits, combined with wide acceptance in the computer marketplace and the ability to support virtually all popular network protocols, make ethernet ideal networking technology for many applications.  

Ethernet Cables

Network protocols

After a physical connection has been established, network protocols define the standards that allow computers and other devices to communicate. A network protocol establishes the rules and encoding specifications for sending data. Internet protocols are the most widely used network protocols.  

Although each network protocol is different, they all share the same physical cabling. This common method of accessing the physical network allows multiple protocols to peacefully coexist over the network media and allows the builder of a network to use common hardware for a variety of protocols.

Common Protocols

TCP – Transmission Control Protocol 
IP – Internet Protocol
TCP/IP - the first two are commonly seen together  
HTTP – hypertext transfer protocol 
FTP – file transfer protocol  
SMTP – simple mail transfer protocol