OBTAIN AN IP ADDRESS BY USING DHCPBEFORE YOU BEGIN THIS EXERCISE, YOU...

3. What is callback and why would you enable it?

Lesson Summary

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You can access a list of installed modems by using the Modems tab of the Phone

And Modem Options dialog box, which is available in Control Panel. From the list

of modems, you can open the Properties dialog box for any modem. You can use

a modem’s Properties dialog box to configure speaker and port options and to

perform diagnostics on the modem.

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Dial-up connections work much like LAN connections, but have additional

options that let you control when the connection is dialed, the number for the

connection, and other criteria for use. To create a dial-up connection, you use the

New Connection Wizard.

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You can configure Windows XP Professional to accept incoming dial-up connec-

tions over a modem or by using VPN. You can choose which of the available

devices on your computer you will allow to accept incoming calls. You can also

specify which user accounts can use the incoming connections.

Lesson 3: Configuring Wireless Connections

Wireless networking offers a degree of freedom—freedom for users of portable and

handheld computers to roam where they will and freedom for companies to place

computers in new locations without having to run network cabling. With that freedom,

however, comes increased vulnerability. Because wireless networking does not share

the same physical security of a wired network, understanding the security options for

a wireless network is of paramount importance. This lesson introduces you to the stan-

dards, implementations, and security options for wireless networks. This lesson also

shows you how to configure a computer running Windows XP Professional to partici-

pate as a client in a wireless network.

After this lesson, you will be able to■ Identify the standards used in wireless networking.■ Explain the basic architecture of wireless networks.■ Identify the security concerns and options of wireless networks.■ Configure a computer running Windows XP Professional as a wireless networking client.Estimated lesson time: 30 minutes

Introduction to Wireless Networking Standards

The primary wireless networking standard is known as 802.11. This standard is devel-

oped and maintained by the Institute of Electrical and Electronics Engineers (IEEE), so

you will often see the standard referred to as IEEE 802.11.

The original 802.11 specification defines data rates of 1 Mbps and 2 Mbps, and uses a

radio frequency of 2.45 GHz. 802.11 provides the foundation for a number of variations

of the standard that IEEE has developed over the years, and it is these variations you

will see implemented in wireless devices on the market today. These variations include

the following:

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802.11b The first real standard to market, which is called 802.11b, was originally

developed in 1999, although it is still in wide use today. 802.11b supports additional

data rates of 5.5 Mbps and 11 Mbps (comparable to the rated speed of traditional

Ethernet) and still uses the 2.45 GHz radio frequency. The advantages of 802.11b

over other standards are that it is typically available at a lower cost and it has the

best overall signal range. However, 802.11b also has the lowest data transfer rate of

the available standards.