Week 5 - Wireless Networking Flashcards
What’s a frequency band?
range of frequencies that are agreed to be used for certain communications
What frequency do FM radio transmission operate in NA?
FM radio transmissions operate at 88-108 MHz in North America
What is a FM broadcast band?
An FM broadcast band is the radio frequency range that the broadcast operates at
What 2 broadcast bands do wireless networks operate on?
2.4 GHz
5 GHz
What layers does the 802.11 standard define how we operate?
802.11 standards define how we operate on the Data Link and Physical layers
What is WAP and how is it defined?
Wireless Access Point
a networking device that allows wireless-capable devices to connect to a wired network
What is used to make sure that incoming transmissions are sent to the right WAP?
Network devices connected to the closest WAP make sure transmissions are sent to the right WAP
What is a receiver address in a 802.11 frame?
A receiver address is the MAC address intended to receive data
What’s a transmitter address in a 802.11 frame? What is it usually the same as?
A transmitter address is the MAC address of where the data was transmitted from
Transmitter address is usually the same as a Source address, depending
What type of addresses are the addresses in an 802.11 frame?
MAC addresses
What are the 6 parts to an 802.11 frame?
- Frame/control (how frame should be processed)
- Duration (how long it is and should listen to it)
- Address 1-4
- Sequence Control (frame order)
- Data payload
- FCS - checksum for CRC like Ethernet does
What are channels when used by a wireless network?
The individual, smaller sections of a frequency band
The specific ranges of microwave and radio frequencies
(highway lanes)
Which Wi-Fi frequency can pass through walls more easily?
2.4 GHz
Which WiFi frequency has the longest range? What is it?
2.4 GHz has the longest range - 150 feet indoors to 300 feet outdoors
How many channels does a 2.4 GHz wifi connection typically have?
11-14 (not as much as 5 GHz)
What can cause interference on the 2.4 GHz frequency?
Microwave ovens, bluetooth and other technology that overlaps that frequency band
What’s the maximum achievable data rate for 2.4 GHz wifi?
600 Mbps
Which Wifi frequency experiences less network interference and congestion?
5 GHz bc it operates on a different frequency band
What’s the wireless range of the 5 GHz frequency?
50 feet indoors, 100 feet outdoors
What is “infrastructure mode”?
client devices that are configured to connect to WAP
What type of traffic can an Access Point serve?
Wired and wireless
For wired the WAP is a bridge between wireless devices and the wired network
How does the AP connect to the network?
Through an Ethernet cable to an Ethernet switch
How do the different 802.11 standards differ? 5
ranges, channels, modulation techniques, transmission bit rates, frequency bands
What prevents 5 GHz radio frequencies from interfering with local radar and satellite communications?
A technology is used called Dynamic Frequency Selection (DFS)
What are the wider bonded channel size for 802.11ac?
80 and 160 MHz
How wide were the channels for the first 802.11a (1999) - Wi-Fi 2 specification?
20 MHz wide
802.11n allowed channel bonding for 5 GHz? What is that?
Channel bonding is when 2 adjacent channels can be combined
What does “dual band” mean?
A separate radio for each band (frequency)
What are the two common data protocol models that show how IoT share data?
- Request/Response
- Publish/Subscribe
What is the Request/Response protocol for IoT data transfer?
The Request/Response protocol is used for communications where servers/clients request and respond with data
Explain what the Publish/Subscribe model is?
The Publish/Subscribe model is for subscribers to a channel who receive new messages from a publisher through a broker.
What are some ways IoT devices collect data around their environment? 3
- Physical location (temperature)
- Metered data like electricity usage
- Equipment data (maintenance status)
Why are data protocols needed for IoT devices?
so applications can receive and format data that humans and automated systems use
What model does HTTP/HTTPS use?
Request/Response
What is HTTP/HTTPS designed for?
Transferring documents
Channel 8 operates at 24.12 MHz
Channel 8 width is 22MHz
What frequency does the signal actually live on?
Between 24.01 MHz to 24.23 MHz
When do WAP perform congestion analysis?
Some when they start up, others dynamically change their channel as needed
As a Google IT support tech, why is it useful to learn about and use wireless channels? 2
Prevent collision domains
Prevent your WAPs from overlapping with neighboring business’s channels
What do WEP and WPA stand for?
WEP - Wired Equivalent Privacy
WPA - WiFi Protected Access
How long is the encryption key for WEP and WPA?
WEP - 40 bits
WPA - 128 bits
What is MAC filtering?
MAC filtering is when you configure your WAP to only allow MAC address connections from trusted devices
Which is the easiest wireless security encryption to crack?
WEP
What does WPA2-PSK stand for?
WiFi Protected Access - Pre-Shared Key
What security protocol generates a PMK?
Pairwise Master Key is generated by the SAE simultaneous authentication of equals
What does SAE stand for?
Simultaneous Authentication of Equals
What does PMK stand for? What is it?
Pairwise Master Key
A complicated handshake that is a multi-step password authentication protocol between WAP and wireless device
What are KRACKs?
KRACKs are Key Re-Installation attacks that happen when they’re in close proximity to a WiFi user that decrypts data and passwords
What prevents a KRACK attack?
SAE (Simultaneous Authentication of Equals)
What are dictionary attacks?
Criminals try to crack short, easy passwords
What does AES stand for?
Advanced Encryption Standard
What does GCMP-256 stand for?
WPA3: Galois/Counter Mode Protocol
Has a longer 256 bit encryption key
What does OWE stand for in WPA3 Enterprise? What does it do?
Opportunistic Wireless Encryption
Encrypts all connections with a unique key (good for open networks)
What is DPP in WPA3 Enterprise security protocols?
WiFi Device Provisioning Protocol
uses QR codes or NFC tags to grant passwordless Wi-Fi access to wireless devices.
What is 384-bit Hashed Message Authentication Mode (HMAC) with Secure Hash Algorithm (SHA)?
Compares hash code that was created from a secret key to hash code received for discrepancies
(similar to an FCS process)
What is Elliptic Curve Diffie-Hellman Exchange (ECDHE) and Elliptic Curve Digital Signature Algorithm (ECDSA)?
Key management and authentication encryption used with faster performance supported by most browsers
Replaces WPA2 4 way handshake
(WPA3 Enterprise)
How do cell networks operate? Over what kind of technology?
Cell networks operate over radio waves like WiFi, specifically over certain frequency bands
How do cell networks differ from WiFi networks?
Cell networks have longer ranges
What’s a simple first step to troubleshoot a mobile device not connected to a network?
Has the connection setting been toggled off? Is it in Airplane mode?
What is a metered connection?
Metered connection is when you’re charged for how much data you use
How do you troubleshoot an unreliable network connection on a mobile device? 3
Is the device too far away from receiving antenna?
Is it reflecting off things, passing through things?
How is the mobile device being held or worn?
What’s an example of a common short-range wireless network?
bluetooth
What does it mean when you pair your devices?
You pair your devices when you connect a wireless peripheral to your mobile device
What is a PAN in terms of wireless protocols?
Personal Area network
What does WiFi stand for?
Wireless Fidelity
What is the IEEE 802.15.4 IoT wireless protocol?
low-cost wireless access protocol for battery-powered IoT devices
What is LR-PAN? What applications does it serve?
Low Rate Wireless Personal Access Network
Industrial and medical applications are served with low-power, low-cost requirements
What is ZigBee?
Zigbee is a low data rate, networking protocol targeted towards automation and remote control applications for IoT devices.
Universal language that makes smart objects on a mesh network easier to operate
It is a LR-WPAN
What is Thread in Wireless Protocols for IoT?
Thread is a low-latency wireless mesh networking protocol that’s based on IPv6 addressing
What is Z-Wave? IoT
Simple, low-powered radio frequency transmissions in a wireless mesh protocol
supports closed networks for security
(100 million devices use this worldwide)
What does WMN stand for? What does it do?
Wireless Mesh Network
it’s a network of self-healing nodes/WAP that forward data to each other to reach a destination
used by popular IoT network protocols (Z-wave, Zigbee)
Difference between Full mesh and partial mesh networks?
Full Mesh Network - All nodes can communicate with each other
Partial Mesh Network - Nodes only communicate with nearby devices
On what GHz does bluetooth operate on?
2.45 GHz
What is NFC?
Near Field Communication
Explain what is NFC
a short-range, low-data wireless protocol that requires:
- the device to be within 2-8 inches of the scanner
- a physical chip/tag embedded on the IoT devices
What is LoRaWAN? What is it designed for?
Long Range Wide Area Network
open source networking protocol to connect battery-powered wireless IoT devices to the internet for WANs
What is a channel?
A channel represents a portion of a frequency band.
What is an ad-hoc network?
Several devices can share the host device’s internet access (like a mobile hotspot)
When set up temporarily, an ad-hoc network is a temporary LAN.
What’s a mesh network?
a group of network devices (like WiFi routers, Extenders, WAPs) that act as a single network
What makes a network self-healing?
When the network can recover on its own when a node fails
What are the 7 data transfer protocols that IoT devices can use at the application layer?
- HyperTextTransferProtocol/HTTP/HTTPS
- Machine to Machine M2M
- Message Queue Telemetry Transport (MQTT)
- Constrained Application Protocol (CoAP)
- Advanced Message Queuing Protocol (AMQP)
- Extensible Messaging and Presence Protocol (XMPP)
- Data Distribution Service (DDS):
What are the 5 new encryption methods for a WPA3-Enterprise?
- GMCP-256 Galois/Counter Mode Protocol
- OWE Opportunistic Wireless Encryption
- DPP Wi-Fi Device Provisioning Protocol
- 384-bit Hashed Message Authentication Mode (HMAC) with Secure Hash Algorithm (SHA)
- Elliptic Curve Diffie-Hellman Exchange (ECDHE) and Elliptic Curve Digital Signature Algorithm (ECDSA)
What does LR-WPAN stand for? What is it? IoT
Low Rate Wireless Personal Area Network
low-cost, low-power consumption set to serve industrial, residential, and medical applications
What frequency does NFC operate on?
13.56 MHz
