What are they?

Homes, businesses or other public areas that require the use of computers are usually networked via local area network (LAN). In the majority of cases a local network consists of a cluster of computers and other hardware and devices that are interconnected via a fixed line or a wireless link to a server. Resources such as network storage, printers and scanners can be shared by the devices in the LAN.

In a home network there might be as few as 2 or 3 users, whereas in a business environment there might be hundreds of users connected to the network.

 

Other important definitions

Topology refers to how the devices in the network are connected. There are a number of specific patterns that can be used, the most common being star, bus, ring or some combination of these. The name actually refers to the physical layout of the system.

Protocols are a set of rules used by computers to control the stream of messages between them. The Open Systems Interconnection (OSI) model was a project by International Standards Organization (ISO) which set the standards with regard to network protocols.

 

Brief history

With the increased use of computers in educational and research facilities in the 1960’s the need for high-speed connectivity between them became a must. The “Octopus” network at the Lawrence Radiation Laboratory was one of the first, followed by the development of Ethernet at Xerox Parc in the early 1970’s. One of the other earlier technologies was ARCNET (Attached Resource Computer NETwork) which was announced in 1977.  It was grown in the 1980s and was used initially for office automation tasks, and afterwards for embedded systems.

Token Ring was another type of LAN technology, endorsed by IBM until the late 1990s, in which stations are organized in a ring topology. Data is transmitted sequentially between ring stations and a control token takes care of access. Eventually Ethernet was adopted as the global standard for LANs, wired and wireless. The original version of Ethernet, which supported a rate of 10Mbps (Megabits per second) progressively evolved to deliver 100Mbps, 1Gbps, 10Gbps, and lately 40Gbps and 100Gbps. Today Ethernet is used from the smallest home network to the largest campus or Data Center environments.

Limitations of local networks

The main limitation of local networks is the one of space, hence the name “local”. They are intended to connect devices within the same home, office, building or campus. Beyond that other technologies are used and these larger networks are referred to as MAN (Metro Area Network), when spanning an urban area, or eventually WAN (Wide Area Network). MAN or WAN connect multiple LANs across geographical distances.

Another limiting factor in LAN design is the number of users and devices on a LAN segment. In larger LANs, connecting hundreds or thousands of devices leads to more complex designs. Different levels of hierarchy are used to separate entities, such as departments in their own segments and connect them to a network core via two or three-tiered hierarchy.

LAN switches, the building blocks of LANs, are subject to the typical environmental limitations of network equipment, such as power requirements, operating temperature range, humidity, etc. Providing adequate and reliable power supply and cooling of this equipment is a primary task in LAN design.

 

Advantages

Home and business networking has many advantages:

  • Installation is simple, and network upgrades and expansion can be done relatively quickly and without too much additional investment. Moving or reconfiguring LANs is also quite straightforward.
  • Data transmission – data can be transmitted between the networked hardware quickly and efficiently so workers in an office or users at home can share and communicate between each other or send data to peripheral devices.
  • Easy to use – users don’t require special skills or training to be able to work over a local network. The only prerequisite is to have basic skills for using a personal computer.
  • Storage capacity – networks also offer a variety of storage solutions depending on the requirements of the home or business user.

Security

There are three main types of threats when it comes to home or business networks:

  • People threats – these can be intentional and unintentional and are by far the most difficult to deal with. People threats start at the system administration level from setting up to maintaining the network. They can also be caused by the users of the network in relation to password/login information, deletion of files or data privacy breeches. Unauthorized use can also be a serious threat for security including access to sensitive information, installation and use of unauthorized hardware or software.
  • Physical Threats – The most frequently occurring problem of this type is issues with electrical power – failure or disturbance – which causes interruption in operations. The consequences can be minor, such as loss of input data to more serious ones like shutdown of the network. Fire and water damage have much more dire consequences but occur very rarely. Hardware failure can be associated with any of the components of the local network and can lead to interruption of services, loss of data or problems with the software.
  • Viruses – the damage caused by viruses can vary a lot depending on the intentions of the author and their introduction to the network is most often due to human error or a combination of that inadequate virus protection in place.
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