Network+ Lesson 12 Wireless Standards

If a WLAN does not need a user to provide credentials to associate with a wireless access point and access the WLAN, what type of authentication is in use?

• IV

• Open

• SSID

• WEP

Answer explanation

Open authentication permits the use of the wireless local area network (WLAN) with no credentials. It is useful in a public and free Wi-Fi hotspot or a guest area in an enterprise.

Which of the following technologies does IEEE 802.11n use to achieve high throughput using multiple antennas for transmission and reception?

• MIMO

• LACP

• FHSS

• DSSS

Answer explanation

IEEE 802.11n uses multiple-input, multiple-output (MIMO) technology to achieve high throughput using multiple antennas for transmission and reception.

A WLAN formed directly between wireless clients without using a wireless AP is referred to as what type of WLAN?

• Enterprise mode

• BSS

• Personal mode

• IBSS

Answer explanation

An independent basic service set (IBSS) is formed directly between wireless clients without using a wireless access point (AP).

Which IEEE 802.11 variant supports a maximum speed of 54 Mbps and uses the 2.4 GHz band?

• 802.11g

• 802.11n

• 802.11a

• 802.11b

Answer explanation

The IEEE 802.11g standard supports a maximum speed of 54 Mbps and uses the 2.4 GHz band.

Which technology do WiFi devices use to gain access to the wireless media?

• RSTP

• DUAL

• SPF

• CSMA/CA

Answer explanation

Wireless local area networks (WLANs) use carrier-sense multiple access with collision avoidance (CSMA/CA) to gain access to the wireless media.

What type of antenna, used in wireless APs and wireless routers in SOHO locations, radiates power equally in all directions?

• Yagi

• Parabolic

• Omnidirectional

• Unidirectional

Answer explanation

The omnidirectional antenna radiates power equally in all directions and is used in wireless access points (APs) and wireless routers in Small office/home office (SOHO) locations.

WEP’s RC4 approach to encryption uses a 24-bit string of characters added to transmitted data such that the same plaintext data frame will never appear as the same WEP-encrypted data frame. What is this string of characters called?

• Initialization vector

• Session key

• Orthogonal descriptor

• Chips

Answer explanation

The string of characters is known as an initialization vector (IV). RC4 uses a 24-bit IV, which is a string of characters added to the transmitted data such that the same plaintext data frame will never appear as the same WEP-encrypted data frame.