Wireless Networking Flashcards
Designed for point-to-point communications with another device, and isn’t compatible with other standards. It may also be prone to interference and have little or no security measures.
RF
A technology which allows identification and communication between nodes using electromagnetic fields.
RFID
Most commonly used for inventory tracking, identification badges, and even implanted chips to identify pets in case they’re lost.
RFID
Operates in the same 2.4 GHz RF band used by Wi-Fi and is commonly used to connect peripherals to computers and mobile devices.
Bluetooth
A set of standards based on RFID, and commonly found on mobile devices such as smartphones and only supports communications up to 20cm away and at speeds up to 424 kbps, so it’s usually only used either for small amounts of data like contactless payment systems or authentication, or else for configuration data that can bootstrap a faster Bluetooth or Wi-Fi connection.
NFC Near Field Communication
A 2.4 GHz radio protocol similar to but separate from Bluetooth which operates at low speeds over distances up to 30 meters, and is used primarily to manage sensors such as fitness trackers, medical devices, and watches.
ANT+
A proprietary wireless standard maintained by Silicon Labs that uses the 800-900 MHz ISM band, with precise frequencies varying by country. supports throughput up to 40 kbps over distances of 10-100m, but it allows nodes to form a mesh network such that even if two nodes can’t directly communicate, they can relay data through intermediate nodes. Used for interoperable monitoring and remote control of home automation systems such as lighting control, thermostats, household appliances, and security systems.
Z-Wave
An open standard based on the IEEE 802.15.4 PAN standards which use a variety of ISM bands, with 2.4 GHz and 915 MHz bands being the most common.
ZigBee
Uses multiple antennas to simultaneously transmit and receive separate data streams on the same channel
MIMO
Devices use haptic confirmation for sharing data wirelessly.
NFC (Near Field Communication)
Devices are paired using a code for sharing data wirelessly
Bluetooth
Devices are placed in close proximity within line of sight for sharing data wirelessly.
IR (Infrared)
Devices are connected via a wire for sharing data or connectivity.
Tethering
Centrally managed from a central wireless access point (WAP) that mediates all communications
Infrastructure networks
Have no WAP: clients communicate directly with each other.
Ad hoc\ or peer-to-peer networks
Supported by some new devices, especially distributed WAPs and IoT devices.
WMN
A string of up to 32 octets that can be used to uniquely identify it to clients
service set identifier (SSID)
Equipment tends to be more expensive and the range is shorter, but it has 23 non-overlapping channels and typically interference is less.
5 GHz ISM
These frequencies support a very high data rate, but typically don’t penetrate walls.
60GHz millimeter wave
Only supported network speeds of 2Mbps, and devices from different manufacturers had poor interoperability.
The original 1997 802.11 standard
Supports speeds of up to 11Mbps on the 2.4GHz band.
802.11.b
Supports speeds of up to 54Mbps on the 5 GHz band
802.11a
Supports speeds up to 54Mbps over the 2.4 GHz band
802.11g
Supports speeds up to 600 Mbps over either the 2.4 GHz or 5 GHz band, if all 4 spatial streams are used. Introduced a number of technologies to boost speed, including MIMO and wider 40MHz channels via channel bonding (HT mode)
802.11n
Supports speeds of up to 6.93 Gbps in the 5GHz band using OFDM encoding, if all 8 spatial streams are used. Uses still-wider 80MHz channels (VHT), more MIMO antennas, and beamforming technology
802.11ac
Original Wi-Fi standard, It uses the RC4 encryption cipher
WEP: Wired Equivalent Privacy
Encrypts traffic using Temporal Key Integrity Protocol (TKIP)
WPA: Wi-Fi Protected Access
Mandatory support for 128-bit encryption using the strong and well-regarded Advanced Encryption Standard(AES) cipher
WPA2
What is the strongest current encryption standard for Wi-Fi?
WPA2 in AES-only mode
Uses a passphrase of between 8 and 63 ASCII characters, manually distributed to each authorized user
WPA-Personal: Also called pre-shared key (PSK)
Connecting clients are only allowed to communicate to an external authentication server, usually RADIUS-based, with a username and password
WPA-Enterprise: Also known as 802.1x mode
Allows the key to be shared with a new device by other methods like a PIN, a push-button pairing mechanism, or NFC pairing
WPS: Wi-Fi Protected Setup
Turns routing off entirely and causes the router to function as a switch and is useful if you want to add a new WAP to a LAN that already has enough router
Bridge Mode
Lets clients dynamically open incoming ports, but instead of individual rules configured on the router, it’s a standard supported by many devices and applications
Universal Plug and Play (UPnP)
Redirect all incoming traffic on a given port or port range to a specific local host
Port Forwarding rules
Opens all ports that aren’t otherwise forwarded to the DMZ host.
Demilitarized Zone (DMZ)
Making sure that time-sensitive traffic like VoIP, streaming video, or games gets handled without delay, even when it means that traditional file transfers such as web or FTP connections take longer.
Quality of Service (QoS)
Troubleshooting that moves down the network stack from network applications down through the operating system
top-down approach
Troubleshooting that moves up through the network stack from physical connection to NIC drivers and the operating system
bottom-up approach
