2.4 Local Area Networks (LANs)

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2.4 Local Area Networks (LANs)

Local Area (and Wide Area) Networks (LANs and WANs) began to grow rapidly because of the need to access data maintained on other computers.

The ticket agent would have to acquire a logon identification from the owner of the other computer and permission to access their computer and database in order to accomplish this. Security of data became a big issue at this time, and still remains a big issue today.

LANs were created to enable the connection of one computer to another to allow users to access the data stored in the different databases on the connected computers (Figure 2-6). In the early days of networking, a computer was connected to the backbone cable. This was a thick cable that would be laid throughout a building so that all the computers in that building could be connected.

Figure 2-6. Early LANs

A more contemporary LAN still runs a cable through the building. Client workstations are connected to the LAN with hubs, and they can access the server and its stored data (Figure 2-7).

Figure 2-7. The Classic LAN

Of course, LANs were capable of considerable expansion.

In the example shown in Figure 2-8, the user can access data on any of the storage devices as long as he or she has a logon to the storage device s associated computer. For only one user , this arrangement would be very fast. However, if you bring too many users onto the LAN, demand becomes severe and the network begins to bottleneck, or slow down.

Figure 2-8. Multiple Computers on a LAN

What s the cause? The slowdown could be related to the speed of the processors, or the number of users requesting data at the same time, or the speed of the storage devices themselves .

The Network Administrator came onto the scene, proving that Information Technology creates at least as many jobs as it eliminates. With general responsibility for maintaining the health of the network, a specific Net Admin responsibility was identifying where the bottlenecks existed. To put it more delicately, performance optimization and capacity planning became key tasks for the Network Administrator.

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Storage Area Networks. Designing and Implementing a Mass Storage System
Storage Area Networks: Designing and Implementing a Mass Storage System
ISBN: 0130279595
EAN: 2147483647
Year: 2000
Pages: 88

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