Page 35 - DCAP311_DCAP607_WIRELESS_NETWORKS

Unit 2: Wireless System Architecture

In Figure 2.6, you can see how two computers are connected with network interface cards and Notes
network cables.
Figure 2.6: Two Computers Connected Through NICs

Source: www.netguidea.com/2012/09/introduction-2-network-interface-cards.html
A device driver, called driver in shorten form, is a specific type of software developed to allow
interaction with a hardware device (in this case NIC). Typically this constitutes an interface
for communicating with the NIC, through the specific computer bus it is connected to. It also
provides commands for transmitting and/or receiving data through the NIC.

Networks (hardware) provide the basic ability of transferring data from one computer to another.
In order to use networks we need a set of rules which all of the network’s members agree on.
Such set of rules is called a protocol.
Communication Protocol is a set of standards designed to specify how computers interact and
exchange messages. A Protocol usually specifies;

z z format for data representation
z z how to handle errors
z z signalling
z z authentication procedures
In order to simplify the design and implementation of protocols, a set of protocols is defined.
Each in the set has different responsibilities instead of the one protocol being responsible for all
forms of communication.

2.1.5 Air Medium

Air is the medium for a wireless network, but to utilize the free supply of this medium you
need equipment and an environment free of interference. In a home network, the infrastructure
might be as simple as a wireless enabled broadband modem, which also acts as router and access
controller, and the wire necessary to connect this to the power outlet and perhaps a shared
printer. In a larger network, multiple routers, repeaters and monitoring systems may be in place,
and whole sections of the network may use wired connections.
You may see the following terms used interchangeably, but basically:

z z A base station is a device whose sole purpose is to connect to the wireless network and
relay information along it.
z z A modem is the device that connects a local network to a remote one.
z z A router enables sharing of an internet connection between multiple devices.
An access controller is a device that sits between the local and remote network and adds a layer
of security to the network, determining whether connections are secure and should be allowed.

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