Section 11: Wireless Networks Flashcards
WiFi IEEE Standard
802.11 (Standard for Local Area Networks)
AdHoc Mode
▪ Wireless devices communicate directly with each other without the need for a centralized access point
▪ Peer-to-Peer connections
Infrastructure Mode
▪ Wireless devices communicate with other wireless or wired devices through a wireless router or access point
AP or WAP
Access Point or Wireless Access Point (Layer 1)
▪ Extends wired LAN into the wireless domain
● Does not interconnect two networks (not a router)
● Functions as a hub
▪ Connects wired LAN and wireless devices into the same subnet
▪ All clients on an access point are on a single collision and broadcast domain
Wireless Router
▪ Gateway device and base station for wireless devices to communicate with each other and connect to the Internet
▪ Often combines many features into one device:
● Wireless Access Point (WAP or AP)
● Router
● Switch
● Firewall
● Fiber, Cable, or DSL modem
WLAN IBSS
Independent Service Set - No access points. AdHoc Mode.
WLAN BSS
Basic Service Set - Only one AP connected to the network. (Infrastructure Mode)
WLAN ESS
Extended Service Set - Multiple APs connected to network. (Also Infrastructure Mode.) (Same Wirless Network Name)
Wireless Mesh Topology
▪ May not use a centralized control
▪ Uses WiFi, Microwave, Cellular, and more
Spread Spectrum Wireless Transmission Terms to know for exam
▪ Direct-Sequence Spread Spectrum (DSSS)
▪ Frequency-Hopping Spread Spectrum (FHSS)
▪ Orthogonal Frequency-Division Multiplexing (OFDM)
▪ Only DSS and OFDM are commonly utilized in today’s WLANs
Which 2.4 GHz channels avoid overlapping frequencies for b/g/n networks?
1, 6 and 11 (Provides enough separation to keep 20MHz of use and fit within the 72MHz of allowable spectrum.)
What is the 5GHz spectrum feature that allows for combining channels?
Channel Bonding
▪ Allows you to create a wider channel by merging neighboring channels into one
802.11a: Operating band / max bandwidth?
5 GHz / 54 Mbps
802.11b: Operating band / max bandwidth?
2.4 GHz / 11 Mbps
802.11g: Operating band / max bandwidth?
2.4 GHz / 54 Mbps
802.11n: Operating band / max bandwidth?
2.4 and 5 GHz / 150 Mbps and 600 Mbps (MIMO)
(aka Wi-Fi 4)
802.11ac: Operating band / max bandwidth?
5 GHz / 3 Gbps (MU-MIMO)
(aka Wi-Fi 5)
802.11ax: Operating band / max bandwidth?
2.4, 5, and 6 GHz / 9.6 Gbps (MU-MIMO)
(aka Wi-Fi 6)
Wireless Security: Four things to know for exam.
Open = No security/protection
WEP = Initialization Vector (The flaw with WEP, Weak)
WPA = TKIP (Replaced the initialization vectors) and RC4 (Encryption - Weak)
WPA2 = CCMP-(Integrity Protocol); AES-(Encryption Mechanism)
EAP
Extensible Authentication Protocol - Authentication using 802.1x (3 Modes)
▪ EAP-FAST - Flexible Authentication via Secure Tunneling
▪ EAP-MD5
▪ EAP-TLS
MAC Filtering
For exam considered a reasonable security measure. Not so much in the real world.
NAC
Network Access Control - Permits/denies access based on devices characteristics.
▪ Checks the OS and antivirus version of client
Captive Portal
▪ Web page that appears before the user is able to access the network resources
▪ Webpage accepts the credentials of the user and presents them to the authentication server
Geofencing
▪ GPS or RFID defines boundaries which can be active or passive
▪ Device can send alerts if it leaves area
▪ Network authentication can use it to determine access
Disable SSID Broadcast
Server Set Identifier
▪ Configures an AP to not broadcast the name of the wireless LAN
(Minor security feature because it can be easily determined. But, can be a layer when using other security features.)
Rogue Access Point
▪ Malicious users set up an AP to lure legitimate users to connect
▪ Can then capture all the packets (data) going through the rogue access point
