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CompTIA A+ Rapid Review: Networking

Objective 2.5: Compare and contrast wireless networking standards and encryption types

Wireless networks are commonly used in home networks, small offices, and even large organizations. PC technicians are often asked to work on these networks and need to have a basic understanding of the various wireless standards that are available and their characteristics. Security is a primary consideration when configuring a wireless network, so you also need to know what encryption types are available, including which ones provide the best security.

Exam need to know...

  • Standards

    For example: Which 802.11 standard is the fastest? Which 802.11 standard uses 5 GHz?

  • Encryption types

    For example: What wireless encryption type is the least secure? Which wireless encryption type provides the best protection?

Standards

Wireless networks are known as 802.11 networks, and there are four primary standards you should know about. They are 802.11a, 802.11b, 802.11g, and 802.11n.

True or false? 802.11a networks broadcast on the 5-GHz frequency range.

Answer: True. 802.11a networks use only the 5-GHz frequency range. They have a maximum speed of 54 Mbps and have the shortest range when compared to the others.

The speed and range of wireless signals is affected by many variables. Physical obstructions such as walls and trees impede the signals. Also, other radio transmissions in the area can affect how far signals can travel. When wireless devices connect, they attempt to connect at the fastest possible speed of the standard without any errors. When devices are far from each other, they use a slower speed to eliminate errors.

True or false? 802.11g networks have the highest possible speed of each of the wireless standards.

Answer: False. 802.11n networks have the highest possible speed with throughputs of 150 Mbps, 300 Mbps, or 600 Mbps. 802.11g networks have a maximum throughput of 54 Mbps.

802.11n uses multiple input multiple output (MIMO) antennas, allowing it to transmit data on two different channels within the same frequency spectrum at the same time. The other standards use a single antenna. 802.11n is also backward compatible with 802.11g.

True or false? 802.11b networks have the lowest maximum speed of each of wireless the standards.

Answer: True. 802.11b networks have a maximum speed of 11 Mbps, which is the lowest throughput of all of the wireless standards.

Table 2-2 shows the characteristics of the four wireless standards.

Table 2-2. Wireless standards characteristics

Standard

Frequency

Maximum Speed

Range

802.11a

5 GHz

54 Mbps

Shortest

802.11b

2.4 GHz

11 Mbps

Medium

802.11g

2.4 GHz

54 Mbps

Medium

802.11n

2.4 GHz and 5 GHz

Up to 600 Mbps

Longest

Encryption types

Encryption types are used to provide security for wireless transmissions. The three wireless encryption types are Wired Equivalent Privacy (WEP), Wi-Fi Protected Access (WPA), and WPA2.

True or false? WPA is the least secure of the different encryption types.

Answer: False. WEP is the least secure of the different encryption types.

Attackers can easily discover the security key used for a WEP encrypted network. Because of this, WEP is not recommended for use.

WPA was created as an interim replacement for WEP. Later, WPA2 was standardized and is now recommended for use whenever possible. WEP, WPA, and WPA2 commonly use a passphrase or a pre-shared key. When joining a network, you need to know the name of the network, the type of security used, and the passphrase.

WPA and WPA2 both can use either Advanced Encryption Standard (AES) or Temporal Key Integrity Protocol (TKIP) to encrypt the data. AES is a widely used standard and recommended for use.

Can you answer these questions?

You can find the answers to these questions at the end of this chapter.

  1. Which 802.11 wireless standard uses the 5-GHz frequency range?

  2. Which 802.11 wireless standard can transmit the most data at a time?

  3. Which encryption type has been broken and should not be used?