Wireless and SOHO Networks (Chapter 7) Flashcards
Why are wireless standards 802.11a and b incompatible?
They use different modulation and operate in different frequencies (a: 5Ghz, b: 2.4Ghz)
What does it mean if a device is labeled with ā802.11b/gā?
The device can operate with both standards.
Which of the older standards commonly conflicts with other devices on the same frequency?
802.11b
Operates in 2.4Ghz, conflicts with microwaves, Bluetooth
What kind of collision handling does 802.11 use?
CSMA/CA
Collision avoidance.
Which standards operate in both 2.4 and 5Ghz?
802.11n (for new improvements from previous standards!)
and 802.11ax
Up to what speed can 802.11n provide?
600Mbps
Which two older standards are compatible with each other?
802.12b/g
How many channels are available for use in the 2.4Ghz range?
11
Which standard is known as WiFi 5?
802.11ac, released in 2014
Which standard is known as WiFi 6?
802.11ax, released in 2019
Up to what speeds can 802.11ac provide?
7Gbps, a massive increase from 600Mbps with n
What is one of the most important new features of 802.12ac?
Beamforming, which sends the signal in a specific direction toward the client
DOES NOT INCREASE THROUGHPUT, just range
Which of the three newer standards operates on only 5Ghz?
802.11ac
Which wireless standard provides the most distance?
802.11n (250m)
What standard and frequency does BT operate on?
802.15 (2.4Ghz)
Same as Zigbee
What does a WAP do?
Adds wireless connections to an Ethernet network
If you have overlapping WAPs what do you need to do?
Use nonoverlapping channels to avoid communications problems. These channels are 1, 6 and 11.
What is long-range fixed wireless?
Point-to-point technology using directional antennas to send and receive. The sending and receiving devices need to be pointed at each other. Obstructions can interfere.
Can you get power from long-ranged fixed wireless?
Yes (a.k.a. WPT, wireless power transfer). Itās the same concept of PoE except itās sent with microwaves or light. The receiving station converts it into electricity.
What technology is a subset of RFID and what is its distance like?
NFC
Very short distance
Used in contactless payments
Do cable and DSL use the same source for internet?
No. DSL uses telephone lines and cable uses cable TV lines
Is DSL or cable faster?
Cable, though the ISP can throttle download speeds with both since you share bandwidth with other customers.
What is channel bonding?
Combining two adjacent wireless channels to create a single, wider channel. This increases bandwidth and can improve data throughput in Wi-Fi networks.
Which standards support channel bonding?
All three newer standards (802.11n, ac, and ax)
What WiFi standard introduced DFS?
802.11n uses Dynamic Frequency Selection to detect radar interference and adjust frequencies accordingly.
What will happen if a 802.11b device connects to a 802.11g router running in mixed mode?
All connected devices will receive a speed of 11 Mbps as the router switches to accommodate.
What is the list of rules on a firewall called?
ACL (access control list)
Frequency and speed of 802.11a
5 Ghz
54 Mbps
Frequency and speed of 802.11b
2.4 Ghz
11 Mbps
Frequency and speed of 802.11g
2.4 Ghz
54 Mbps
Speed and frequency of 802.11n
2.4 Ghz + 5 Ghz
600 Mbps
Frequency and speed of 802.11ac
5 Ghz
7 Gbps
Big jump from 600Mbps (n)
Frequency and speed of 802.11ax
2.4 Ghz + 5 Ghz
10 Gbps
What is WPA? Whats the weakest?
Wifi protected access
WEP is the weakest, next is WPA
What is MIMO and what standards support it?
Using multiple antennas to transmit more data at once
802.11n
Which standards support MU-MIMO?
802.11ac and ax
Which standard has a new sleep feature that lowers power usage?
Wifi 6 (ax)
What did 2G consist of?
2 global standards:
CDMA and GSM (not converged)
Good for voice, but very bad for sending data
What features did 3G introduce?
GPS, mobile TV and streaming video and audio (video on demand)
After 3G, what was the significance of LTE (4G)?
It was a converged standard. Companies that used to be GSM or CDMA can now used one standard (LTE) for sending data over a wireless network.
What does 5G provide over the other generations?
Greatly enhanced speeds. Some 5G networks can perform at around 10 gigabits per second.
What is mobile PRL?
Preferred Roaming List
Allows your phone to understand where the appropriate towers are for the network that it happens to be using
Used with CDMA
How are PRL updates performed?
OTA (over the air)
Which standard was more globally accepted and allowed for SIM card transfer?
GSM (Global System for Mobile Communications)
This was AT&T, T-Mobile
How did GSM allow multiple people to communicate over the same frequency?
Multiplexing
How did CDMA allow multiple users to communicate at the same time?
Code division
Each person used a unique code that was used to filter out irrelevant codes
Verizon and Sprint
What download rates did LTE (4G) support?
150 Mbps
What is LTE-A and what does it provide?
LTE-Advanced
Increase speeds from 150 to 300 Mbps
What is WISP?
Wireless internet service provider
What delivery method does WISP use?
Fixed point-to-point broadband internet
Might use a dish or antenna
What is the most important device in a SOHO network and what functionalities does it have?
The SOHO router
Contains connections for ethernet, wifi, firewall and telephone
Usually have a switch built in as well
Is probably DSL
