Wireless Technology

Wireless Technology

Wireless networks come in many different forms, cover various distances, and provide a range of low to

high bandwidth depending on the type installed. Wireless LAN – Wireless LAN enable Laptop users to

access the Network of a company.

Basic Wireless Devices

1. Wireless Access Points,

2. Wireless Network Interface Card (WNIC),

3. Wireless Antennas.

Wireless Access Points

In the wireless networks, you’ll find a central component such as a switch that’s there to connect

hosts together and allow them to communicate with each other.

Only that device is known as a wireless access point (AP) instead.

Wireless Network Interface Card (WNIC)

Every host you want to connect to a wireless network needs a wireless network interface card

(WNIC) to do so. Basically, a wireless NIC does the same job as a traditional Ethernet NIC, only

instead of having a socket/port to plug a cable into; the wireless NIC has a radio antenna. It

would be difficult to buy a laptop today without a wireless card already built in.

Wireless Antennas

Wireless antennas work with both transmitters and receivers. There are two broad classes of

antennas on the market today: omnidirectional (or). Wireless access points have at least one

antenna. Usually there’s two for better reception (referred to as diversity) and an Ethernet port

to connect them to a wired network.

Wireless Standards (The 802.11 Standards)

Standard Speed Frequency (GHZ) Segment Length

802.11b 11 Mbps 2.4 150 to 350 m

802.11a 54 Mbps 5 75 to 175 m

802.11g 54 Mbps 2.4 100 to 300 m

802.11n 74 Mbps 2.4/5 250 to 300 m

Wireless Technology

Wireless Topologies

Now that I’ve discussed the very basics of wireless devices used in today’s simple networks, I want to

describe the different types of networks you’ll run across or design and implement as your wireless

networks grow.

These include the following:

1. IBSS

2. BSS

3. ESS

Independent Basic Service Set (Ad Hoc) (IBSS)

Using an ad hoc network is the easiest way to install wireless 802.11 devices. In this mode, the

wireless NICs (or other devices) can communicate directly without the need for an AP.

Wireless Technology

Basic Service Set (BSS)

A basic service set (BSS) is the area, or cell, defined by the wireless signal served by the AP. It can

also be called a basic service area (BSA) and the two terms, BSS and BSA, can be interchangeable.

Even so, BSS is the term most commonly used to define the cell area.

Extended Service Set (ESS)

A good thing to know is that if you set all your access points to the same SSID, mobile wireless

clients can roam around freely within the same network. This is the most common wireless

network design you’ll find in today’s corporate settings.

Doing this creates something called an extended service set (ESS), which provides more coverage

than a single access point and allows users to roam from one AP to another without having their

host disconnected from the network. This design creates the ability to move more or less

seamlessly from one AP to another. APs configured with the same SSIDs in an office, thereby

creating the ESS network.

NOTE:- ( SSID is a basic name that defines the BSA transmitted from the AP. You’ve probably seen

that name pop up on your host when looking for a wireless network. The SSID can be up to 32

characters long. It normally consists of human readable ASCII characters, but the standard doesn’t

require this. The SSID is defined as a sequence of 1 to 32 octets, each of which may take any value.)

Wireless Technology

Wireless Security

Open Access

All Wi-Fi Certified wireless LAN products are shipped in “open-access” mode, with their security

features turned off. While open access or no security may be appropriate and acceptable for

public hot spots such as coffee shops, college campuses, and maybe airports, it’s definitely not

an option for an enterprise organization, and likely not even adequate for your private home

network.

SSIDs, WEP, and MAC Address Authentication

SSID Authentication- Two types of authentication were specified by the IEEE 802.11

committee: open authentication and shared-key authentication. Open authentication involves

little more than supplying the correct SSID—but it’s the most common method in use today.

WEP Authentication- WEP is a type of shared-key authentication With shared-key

authentication, the access point sends the client device a challenge-text packet that the client

Wireless Technology

must then encrypt with the correct Wired Equivalency Privacy (WEP) key and return to the

access point. Without the correct key, authentication will fail and the client won’t be allowed to

associate with the access point. Without the correct key, authentication will fail and the client

won’t be allowed to associate with the access point

MAC Address Authentication- Last, client MAC addresses can be statically typed into each

access point, and any of them that show up without that MAC addresses in the filter table would

be denied access. Sounds good, but of course all MAC layer information must be sent in the

clear—anyone equipped with a free wireless sniffer can just read the client packets sent to the

access point and spoof their MAC address.

NOTE:-

Encryption Methods

There are two basic types of encryption methods used in most wireless networks today:

TKIP and AES. We’ll cover TKIP first

Temporal Key Integrity Protocol (TKIP):- Temporal Key Integrity Protocol (TKIP)

which is based on the RC4 encryption algorithm. TKIP first gained respect in the

WLAN world due to the protections it affords the authentication process, but it is

also used after that completes to encrypt the data traffic thereafter.

Advanced Encryption Standard (AES):- Both WPA/2 and the 802.11i standard call

for the use of 128-bit Advanced Encryption Standard (AES) for data encryption.

It’s widely considered the best encryption available today and has been approved

by the National Institute of Standards and Technology (NIST). It’s also referred to

as AES-CCMP, or AES Counter Mode with CBC-MAC authentication.

Wi-Fi Protected Access (WPA)

Wi-Fi Protected Access (WPA) is a standard testing specification developed in 2003 by the Wi-Fi

Alliance, formerly known as the Wireless Ethernet Compatibility Alliance (WECA). WPA provides

a standard for authentication and encryption of WLANs that’s intended to solve known security

problems existing up to and including the year 2003. WPA is a step toward the IEEE 802.11i

standard and uses many of the same components, with the exception of encryption—802.11i

uses AES encryption.

Wireless Technology

WPA or WPA2 Pre-Shared Key

WPA or WPA2Pre-Shared Key (PSK) is a better form of wireless security than any other basic

wireless security method mentioned so far.

WPA or WPA2 Enterprise

WPA and WPA2 support an enterprise authentication method. This is called Extensible

Authentication Protocol (EAP). Understand that EAP isn’t a single method, but a framework that

enhances the existing 802.1x framework.