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The Controller, Access Points and Convergence Software solution

A31003-W1010-A100-1-7619, July 2005

12 HiPath Wireless Controller, Access Points and Convergence Software V3.0: User Guide

HWC_Intro.fm

What is the Controller, Access Points and Convergence Software system?

2.1.1 Conventional wireless LANS

At its simplest, wireless communication between two or more computers requires that each one

is equipped with a receiver/transmitter – a WLAN Network Interface Card (NIC) – capable of

exchanging digital information over a common radio frequency. This is called an ad hoc

configuration. An ad hoc network allows wireless devices to communicate together. This is an

independent basic service set (IBSS).

An alternative to the ad hoc configuration is the use of an access point. This may be a dedicated

hardware router or a computer running special software. Computers and other wireless devices

communicate with each other through this access point. The 802.11 standard defines Access

Point communications as devices that allow wireless devices to communicate with a

“distribution system”. This is a basic service set (BSS) or infrastructure network.

For the wireless devices to communicate with computers on a wired network, the access points

must be connected into the wired network, and provide access to the networked computers.

This is called bridging. Clearly, there are security issues and management scalability issues in

this arrangement.

Figure 2-1 Standard wireless network solution

The wireless devices and the wired networks communicate with each other using standard

networking protocols and addressing schemes. Most commonly, Internet Protocol (IP)

addressing is used.

While this topology works well enough for small installations, as the network grows the difficulty

of setting up and administering all the individual access points expands as well. When the

expanding network has to cope with a large number of wireless users all signing on and off at

random times, the complexity grows rapidly. Imagine, for example, a university library filled with

professors and students – all equipped with laptops. Or a conference full of delegates and

exhibitors.

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Siemens C10 Betriebsanweisung Seite 14