29-06-2012, 05:15 PM
Seminar on Local Area Networks
Local Area Networks.ppt (Size: 386.5 KB / Downloads: 91)
Overview
Traditionally, communications networks can be viewed in 3 categories:
Wide Area Networks (WANs), which span a very large geographical area, such as from city to city or across countries and oceans. WANs are usually operated by transmission service providers.
Metropolitan Area Networks (MANs), which span a large area such as a city, or company sites in different locations within the same city. MANs are usually operated by organizations.
Local Area Networks (LANs), which span a limited area such as a company complex, a building, a campus, or even a small office. LANs are usually operated by a single organization.
In recent years, the so-called Personal Area Networks (PANs) become more and more popular. This is due to the advance in home broadband access so that multiple stations and peripherals form a small network in a single residential home. Topics regarding LANs, MANs and PANs will be discussed in the class.
Local Area Networks (LANs)
Local Area Networks are privately-owned networks within a small area, usually a single building or campus of up to a few kilometers. Since it is restricted in size, that means their data transmission time can be known in advance, and the network management would be easier.
Motivations for Local Area Networking
Local area networks are usually privately owned with limited coverage, this means that the underlying network technologies and network services may be freely selected. This leads to network architectures markedly different from those of Wide Area Networks.
The growing demand for local area networks is due to technical, economic and organizational factors:
Cost reductions through sharing of information and databases, resources and network services.
Increased information exchange between different departments in an organization, or between individuals.
The trend to automate communication and manufacturing process.
Improve the community security.
Increasing number and variety of intelligent data terminals, PCs and workstations.
Various Local Area Networks
A local area network is a small group of interconnected workstations and associated devices that share the resources within a small geographic area. Usually, a local area network may serve as few as several users or many more.
The nowadays main local area network technologies are:
Ethernet (Fast Ethernet, Gigabit Ethernet, 10G Ethernet)
Fiber Channel
Hipper LAN
Token ring
ATM LAN
FDDI (Fiber Distributed Data Interface)
Wireless LAN
……..
There are also some other technologies such as 100VG, token bus,
ARCnet, but those are almost obsolete.