Networking Ch 9 Quiz Review

Carrier sense multiple access with collision avoidance (CSMA/CA), used by 802.11 wireless networks, is an example of what?

• Communication path sharing

• Near-field communications

• Virtual LANs

• Cybersecurity

Answer explanation

Carrier sense multiple access with collision avoidance in computer networking, is a network multiple access method in which carrier sensing is used, but nodes attempt to avoid collisions by transmitting only when the channel is sensed to be "idle". When they do transmit, nodes transmit their packet data in its entirety.

Match the following

• FHSS

• Encodes data over a wireless network using non-overlapping channels.

• OFDM

• Makes the transmitted bandwidth signal wider than the data stream needs.

• DSSS

• Transfers data over a radio signal by switching channels at random within a larger frequency band.

A wireless network SSID groups wireless devices together into the same logical network.

• True

• False

If you have a wireless radio system running on 2.4GHz will it interfere with your 802.11g wireless network?

• Yes

• No

Answer explanation

802.11g wireless networks also run on the 2.4GHz band.

Is 802.11n backward compatible with 802.11b?

• Yes

• No

Answer explanation

802.11n is a popular choice for ugrading older networks "in place", where older APs will still be running with newer ones.

802.11ac is also backward compatible, but costs more to implement.

If money is an issue and you don't need GHz speed, go with 802.11n.

What can decreasing the beacon interval do?

• Allow devices to connect faster

• Improve bandwidth

• Lower the chance that the network can be hacked

• Increase the number of devices that can connect at one time

Answer explanation

A beacon is a packet broadcast sent by the router that synchronizes the wireless network. A beacon is needed to receive information about the router, included but not limited to SSID and other parameters.

The beacon interval is simply the frequency of the beacon – how often the beacon is broadcast by the router. Most routers are automatically set to a default of 100 milliseconds.

Network ​ (a)   , like WPA2, helps prevent your information from being seen by third parties.

• encryption
• SSIDs
• VLANs
• encapsulation
• addressing

Answer explanation

Network encryption, such as that provided by the WPA2 standard, makes it much harder for a third party to see your data.

With a 12 character encryption key, it would currently take 1000 years to brute-force an encrypted data packet to see its contents.

The ​ (a)   protocol is well known for its use in the home security and home automation industry, uses a mesh topology, makes devices act as repeaters, and has a low data transfer rate?

• Z-wave
• NFC
• 801.11ac
• Ant+
• 802.11ac

Answer explanation

Z-Wave is a wireless communications protocol used primarily for residential and commercial building automation. It is a mesh network using low-energy radio waves to communicate from device to device, allowing for wireless control of smart home devices, such as smart lights, security systems, thermostats, sensors, smart door locks, and garage door openers.

What is a common problem for wireless routers left in their default configurations?

• Overlapping channels

• Bandwidth limitations

• Conflicting SSIDs

• Lack of security

Answer explanation

There are a limited number of network "bands" and many manufacturers set all of their devices to use the same band(s).

​ (a)   is built-in to all consumer wireless routing devices.

• NAT
• Z-Wave
• 802.11x
• Kerberos

Answer explanation

All consumer wireless routing devices have NAT (Network Address Translation) built-in. This allows all of your home devices to share a network, but have a single IP address for the Internet.