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How to network computers

Connecting computers together to form a network, and connecting school, lab, and classroom networks to the Internet can further multiply the educational value and impact of computers in schools. There are a variety of options for creating classroom, lab, and school computer LANs.

Peer-to-Peer Networking
As with all networked computers, users can share files and resources located on computers in the network, but there is no file server or central computer to manage network activity. One or more of the computers in a peer-to-peer network can provide centralized services such as printing and access to the Internet. Most desktop operating systems come with software to enable peer-to-peer networking once the computers are connected by some cable or wireless networking infrastructure.

Peer-to-peer networking is good for small networks where a centralized file server is not needed and network security is not a major issue. This type of networking is less expensive and most common computer operating systems (Mac OS and Windows 95/92/Me/2000/XP) come with software to establish it.

Client/Server Networking
As a computer network grows in size and complexity, it may be necessary to shift to a client/server style of network using more advanced network operating software. In these networks, one computer centralizes such functions as storing common files, operating network e-mail delivery, and providing access to applications and peripherals such as printers.

Advantages:

  • Scalable: more clients and servers can be added to the system without changing the network significantly
  • Easier to manage, administer, and secure than peer-to-peer networks

Disadvantages:

  • Because of the need to have a central “dedicated” server, initial costs are higher
  • More complex to set up and maintain than stand-alone computers and peer-to-peer networks, often requiring schools to hire a technician to oversee the network
  • If the server fails, all network functions fail
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Thin-Client/Server Networking
A thin-client/server network is similar to a traditional client/server network, except that the client is not a freestanding computer capable of operating on its own. Rather, thin clients are desktop appliances or network devices that link the keyboard, monitor, and mouse to a server where all applications and data are stored, maintained, and processed. The server, often called an application server, is built to provide all networking services and computer calculations. Since all network and computer services are centralized, all maintenance and upgrading is done at the server; there is no need to service the clients.

Advantages:

  • Even though initial purchase costs are usually higher than with traditional PC/server networks, lifetime costs or total cost of ownership can be significantly less.
  • Thin-client/server networks are also easier to install than traditional client/server networks.
  • Since the client appliances cannot function without the server, there is little risk of theft.
  • Thin-client systems are very efficient at providing access to the Internet
  • Because the client appliances have few moving parts and limited functions, thin-client/server networks are more reliable and stable than traditional network systems.

Disadvantages:

  • Some thin-client/server networks have little educational software written to run on thin-client servers running a version of UNIX. Most of these servers come with special emulation software, but this is usually an incomplete solution: software often runs slower and some applications fail to function.
  • Since many thinclient/ server networks are based on a type of UNIX operating system, skills with UNIX are needed to set up and administer. However, if schools have no staff with these skills, but do have access to the Internet, it is possible to have a technician at some remote site administer and maintain the network. This enables a school district to have one highly skilled technician manage thin-client/server networks in several schools, thus reducing management costs further.

Even though thin-client/server network systems are so far quite uncommon in K-12 educational environments, they are a viable alternative to traditional client/server network systems. A careful assessment of total cost of ownership and the availability of technical skills at a school or school system can help planners decide if the thin-client/server network is best for their needs.

Case study

Thin Client in UK School
Hobbs Hill Wood in the UK has installed a new 35-seat ICT suite that is the first of its kind in any UK primary school, based on innovative thin client computing that does not require individual PCs on the desktops. Thin client ICT suites are not only easier to run and maintain, they provide powerful and reliable computing that will stay up-to-date far longer than a room full of PCs. For teachers that are continually frustrated by PCs that go wrong, thin client restores confidence in computer technology.

Connecting Computers
There are essentially three ways to connect computers to form LANs: cables, wireless, and power line systems.

Cabled LANs

Advantages:

  • Cabled networks provide reliable, high-speed—up to 100 Mb per second— transmission of network traffic.
  • Several hubs can be connected together to allow larger numbers of computers to be networked together.
  • Because cable systems are more common than the other two options, it is usually possible to find firms and technicians with the skills needed to install quality cable LAN systems.

Disadvantages:

  • Installing cabling in older buildings or in schools with thick walls built of brick and cement can be expensive, difficult, and time-consuming. To provide a sufficient number of individual connections for each computer, and to allow for flexible arrangement of computers in a room, many ports and cables must be installed.
  • Each cable connected to a computer must be connected also to a network hub, an electronic device that controls the flow of network traffic between individual computers and the system’s server, usually in clusters of 20 to 30 cables. Hubs usually are housed in shielded and locked network closets to protect the hubs and prevent people from accidentally rearranging the network cables.

Wireless LANs
Increasingly popular, this type of system does not require cables to connect computers to each other and to the server and shared peripherals. Instead, wireless network adapters (receivers) are installed in all computers that will be part of the network . One or more wireless network hubs/transmitters are connected to the server, usually by a cable. Several wireless network hubs can be connected to each other in a daisy chain. Network traffic is then transmitted by the hub to each computer and to and from the server.

Wireless LANs have many advantages:

  • Can be installed and configured in a very short time, since limited or no construction is needed
  • Allow for a high degree of flexibility. Computers, especially laptops, can be moved around a room or building, within the range of the network signal, without losing their connection to the LAN.
  • They can be less costly to install and use than conventional cabled systems.
  • They allow schools to create customized LAN systems covering single rooms or whole sections of the school.
  • They also can be mixed with cabled systems to create greater flexibility.
  • Over the next few years, the speed and range of transmission will increase, and reliability and security will improve.

Disadvantages:

  • The speed of network traffic depends on how many computers are using the hub’s bandwidth simultaneously.
  • Distance from the hub and thickness and character of walls between the transmitter and receiver can affect the speed and quality of the network signal significantly.

Power Line LANs
Power line networking (PLN) currently is capable of providing reliable network communication speeds between 250Kbps and 500Kbps for six to 20 network access points. Higher-speed systems, ranging from two to 12 Mbps, are also available. Equipment costs are higher than conventional and wireless networking technologies, but these are expected to fall as technical improvements are made and larger-scale systems become available.