CompTIA A+ Chapter 22, Wireless Networking

IrDA

(Infrared Data Association) Older method of data transfer. Uses line of sight, distance of approximately one meter and speeds of approximately 4 Mbps.

WPS

(Wi-Fi Protected Setup). Works one of two ways. Some devices use a push button and others use a password or code.

WEP

(Wired Equivalent Privacy). Early on, Wi-Fi developers introduced the Wired Equivalent Privacy protocol to attempt to ensure that data is secured while in transit over the air waves. Uses 40-bit encryption.

Bluetooth technology enables computers to link into what sort of network? (a) Bluetooth area network (BAN) (b) Personal area network (PAN) (c) Local area network (LAN) (d) Wide area network (WAN)

(b) Bluetooth creates personal area networks

What is the name for the common omni-directional antennas found on wireless access points? (a) Bipole antennas (b) Dipole antennas (c) Omni antennas (d) RF antennas

(b) Standard Omni-directional antennas are called dipole antennas.

Three methods wired networks use to secure access to the network itself and secure the data being transferred.

MAC address filtering, Authentication, Data encryption.

MAC address filtering

Most WAPs support MAC address filtering, a method that enables you to limit access to your wireless network based on the physical, hard-wired address of the units' wireless NIC. Mac address filtering is a handy way of creating a type of "accepted users" list to limit access to your wireless network, but it works best when you have a small number of users.

802.11n

Operates in 2.4 GHz and 5 GHz (dual band). Speeds up to 100+ Mbps. Range 300+ feet. The 802.11n specification requires all but hand-held devices to use multiple antennas to implement a feature called multiple in/multiple out (MIMO), which enables the devices to make multiple simultaneous connections.

802.11g

Operates in 2.4 GHz frequency range. Speeds 54 Mbps Range approximately 300 feet.

802.11b

Operates in 2.4 GHz frequency range. Speeds up to 11 Mbps. Range approximately 300 feet.

802.11a

Operates in 5 GHz frequency range. Speeds up to 54 Mbps. Range of approximately 150 feet.

802.11ac

Operates in 5GHz frequency range. Speeds up to 1+Gbps. Range 300+ feet. 802.11ac is a natural expansion of the 802.11n standard, incorporating even more streams, wider bandwidth, and higher speed. The latest versions of 802.11ac include a new version of MIMO called Multiuser MIMO (MU-MIMO).

Ad hoc mode

Sometimes referred to as "peer-to-peer" mode, with each wireless node in direct contact with every other node in a decentralized free-for-all. Ad hoc mode networks are suited for small groups of computers (less than a dozen or so) that need to transfer files or share printers.

SSID

The Service Set Identifier (SSID) parameter- also called the network name- defines the wireless network.

WPA

The Wi-Fi Protected Access (WPA) protocol addresses the weakness of WEP and acts as a security protocol upgrade to WEP. WPA uses the Temporal Key Integrity Protocol (TKIP), which provides a new encryption key for every sent packet.

Exam Tip

To achieve a good compromise in supporting connections to clients with different antenna polarization, orient the WAP antennas on a 45-degree angle.

WPA2

Wi-Fi Protected Access 2 uses (WPA2) uses the Advanced Encryption Standard (AES), among other improvements, to provide a secure wireless environment.

WAP

Wireless Access Point. A WAP centrally connects wireless network nodes in the same way that a hub connects wired Ethernet PCs. Many WAPs also act as switches and Internet routers.

Infrastructure mode

Wireless networks running in infrastructure mode use one of more WAPs to connect the wireless network nodes to a wired network segment. A single WAP servicing a given area is called a Basic Service Set (BSS)