Chapter 20: Wireless Networks Flashcards
IEEE 802.11
WiFi standard
Connecting NIC to a client
Through a PCIe port or external USB
WAP
Wireless Access Point
Act like a hub, but could also be routers/switches
PoE
Power over Ethernet
Must come from a PoE capable switch
PoE Standards
802.3af (PoE)
802.3at(PoE+)
802.3bt (PoE++)
PoE Injector
Pushes PoE up to 100m
CSMA/CA
Carrier Sense Multiple access/collision avoidance
client will listen to see if another client is broadcasting, then waits random time before retrying it’s own broadcast
Due to all the overhead of constant frames, can impede performance
RTS/CTS
Request to Send/Clear to Send
Protocol that asks permission, then acts once permission is received
RTS frame gets sent, CTS frame gets received
ACK
Acknowledgement Frame
Client waits for this after sending data before next packet is sent
BSS
Basic Service Set - the WAP for a particular area
EBSS
Extended Basic Service Set - Multiple WAPs
Repeaters/Extenders
Rebroadcast signals to cover dead zones
Long Range Fixed Wireless
Uses directional antennas, interconnects remote buildings, can reach up to miles
Also known as point-to-point connections
May use proprietary protocols, may need FCC approval, may have reserved channels
WMN
Wireless Mesh Networks - devices act like routers, forwarding traffic.
devices are not WAPS, but “nodes.” Can communicate to each other, even if one node happens to be outside of another node’s range, as long as they have a path through intermediary nodes
3 methods of wireless security (and the two A+ methods)
1) MAC Address Filtering
2) Authentication
3) Data encryption
1) Disable broadcast (hidden network)
2) Change your channel
SSID
Service Set Identifier (network name)
SSID practices
1) Always change the default
2) Each WAP needs to share SSID in a network
3) SSID is included in all packets
4) disabling SSID broadcast hides network
WAP Setup
1) Consider location/placement
2) Decrease radio power so signal only reaches desired limit (trial and error)
3) Disable guest access
4)MAC address filtering (WAP will store given MACs)
Depreciated security methods
WEP (Wired Equivalent Privacy)
WPA (Wi-Fi PRotected Access)
WEP uses encryption level, passphrase, and a default key
WPA uses Personal/Pre-shared Key (PSK) or Enterprise configuration
WPS
Wi-Fi Protected Setup
WPA2
Uses AES (Advanced Encryption Standard)
Also compatible with TKIP (Temporal Key Integrity Protocol)
TKIP is an older encryption method, typically used for backwards compatibility
WPA3
Upgrades some security and usability issues with WPA2
Spread-spectrum
Radio waves send data in small, discrete chunks (how Wi-Fi works)
Bands for IEEE 802.11
2.4GHz, 5GHz, 6Ghz
