Page 95 - DCAP309_INFORMATION_SECURITY_AND_PRIVACY

Unit 7: Network Security

lines (coaxial cables, fibre optic cables, etc.) and the intermediate switching elements also called Notes
‘routers’.

Figure 7.2: Wide Area Networks

The main function of a router is to receive the transmitted data and then select an appropriate
channel to forward it to the destination host or to another router. When a data packet arrives at
a router it is stored in the router until the output transmission line is free and is then transmitted
or forwarded to destination host.

The broadcast type Wide Area Networks (WANs) use a satellite or ground radio system. All or
some routers have antennas through which they can receive the incoming signal from the
satellite. When a ground radio system is being used the routers can communicate between each
other. It may also be possible that in a network, while some routers receive their outputs
through their antennas, others are point to point type.

Did u know? Wide Area Networks are also referred to as Long Haul Networks (LHNs).

7.2.3 Metropolitan Area Network (MAN)

A Metropolitan Area Network (MAN) is one of a number of types of networks. A MAN is a
relatively new class of network; it serves a role similar to an ISP, but for corporate users with
large LANs. It is a network that interconnects users with computer resources in a geographical
area larger than that covered by even a large local area network (LAN) but smaller than the area
covered by a wide area network (WAN). The term is applied to the interconnection of networks
in a city into a single larger network (which may then also offer efficient connection to a wide
area network). It is also used to mean the interconnection of several local area networks by
bridging them with backbone lines. This is sometimes referred to as a campus network. Large
universities also sometimes use the term to describe their networks. A recent trend is the
installation of wireless MANs.

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