Wireless Networking

Question 1

Wireless Standards

Answer 1

• Wireless networking (IEEE 802.11)
  
  • Institute of Electrical & Electronics Engineers
  • Managed by the IEEE LAN / MAN
  • Standards committee (IEEE 802)

-Many updates over time

• The popular standards
  
  • 802.11a , 802.11b , 802.11g , 802.11n & 802.11ac

Question 2

802.11a

Answer 2

• One of the original standards (1999 October)
• Operates in 5Ghz range
• 54 Megabits per second (Mbit/s)
• Smaller range than 802.11b
  
  • Higher frequency is absorbed by other objects
  • Rule of thumb 1/3 the range of 802.11b or 802.11g

Question 3

802.11b

Answer 3

• Also an original 802.11 standard (1999 October)
• Operated in the 2.4Ghz range
• 11 Megabits per second (Mbit/s)
• Better range than 802.11a (less absorption problem)
• More frequency conflict
  
  • Baby monitors , cordless phones , Bluetooth

Question 4

802.11g

Answer 4

• Upgrade to o802.11b (2003 June)
• Operates in 2.4Ghz range
• 54 Megabits per second (Mbit/s)
• Backwards compatible with 802.11b
• Same frequency problems

Question 5

802.11n

Answer 5

• Upgrade to g , b , & a (2009 October)
• Operate in 5Ghz or 2.4Ghz range
• 600 Megabits per second (Mbit/s)
• Use MIMO = Multiple - input Multiple - output
  
  • 4 streams @ 150 Mbit/s = 600mbit/s

Question 6

802.11ac

Answer 6

• Approved January 2014
• Operates in the 5Ghz band
• Increase channel bonding (larger bandwidth)
• Denser signaling modulation (faster data transfer)
• Eight MIMO streams
  
  • Nearly 7 gigabits per second

Question 7

Wireless Encryption

Answer 7

• All wireless computers are radio transmitters and receivers
  
  • Anyone can listen

-Solution : Encrypt the data

• Only people with password can transmit and listen
  
  • WPA encryption

Question 8

Wired Equivalent Privacy

WEP

Answer 8

• Different levels of encryption key strength
  
  • RC4 stream cipher
  • 64bit or 128 bit key sizes
• WEP Cryptographic Vulnerabilities Identified in 2001
  
  • Strongly non-random
  • Can easily discover WEP key

Question 9

WiFi Protected Access

WPA

Answer 9

• WPA : RC4 with TKIP (Tempered key Integrity Protocol)
  
  • Initialization vector (IV) larger & encrypted hash
  • Every packet gets unique encryption key
  • A short term work around
• WPA2 = Uses AES (Advanced Encryption Standard
  
  • CCMP (Counter Mode with Cipher Block Chaining Message Authentication Code Protocol) Replaced TKIP
• WPA2 Enterprise adds 802.1X
  
  • Authentication Server Authentication