Unit 1 Flashcards
How long can you run an Ethernet cable?
100 meters
How long can you run a fibre cable?
550 metres
What are some advantages of wireless network?
Fast installation, no wiring, access to network anywhere in range
What are some disadvantages to wireless networking?
Lower security, slower network, interference
What are the WiFi modes?
Ad Hoc Mode, Infrastructure mode, Mesh Mode, Monitor Mode, Promiscuous Mode, Repeater Mode, Bridged Mode
What is Ad Hoc Mode?
Independent devices without any infrastructure (I/BSS)
What is Infrastructure Mode?
Consists of APs, BSA (Basic Service Area, SSID, Distribution system (router)
What is Mesh mode?
Access points can communicate to all other access points, if one goes down it reconnects to another node
What is Monitor mode?
Sniffing raw traffic, used for design, does not need to be on authenticated
What is promiscuous mode?
Sniffing raw traffic on the network, after is has been connected/authenticated
What is repeater mode?
Rebroadcasts existing WiFi network
What is bridged mode?
Borrows existing wireless internet using a different SSID and password (two networks, one internet)
What does a WLAN controller do?
Extended Service Set (different channels), creates large networks and controls devices on them
What are the IEEE standards?
802.11b, a, g, n, and ac
What are the primary differences between 2.4 and 5 Ghz?
11 channels vs 24 channels
5 Mhz apart vs 20 mhz apart
20 mhz wide vs 20-40 mhz
3 non-overlapping channels vs all
What standards are 2.4 Ghz?
B, G, N
What standards are 5 Ghz
A, N, AC
What has more interference, 2.4 or 5 ghz?
2.4 ghz
What is the top speed of 802.11 n
600 mbits/s
What is the top speed of 802.11a/g
54 mbits/s
What is the top speed of 802.11 ac
6.93 Gbits/s
What does FHSS stand for?
Frequency Hopping Spread Spectrum
What does DSSS standard for
Direct-Sequence Spread Spectrum
What does OFDM stand for?
Orthogonal Frequency-Division Multiplexing
What are the differences between modulations FHSS, DSSS, and OFDM?
FHSS: Radio hops (one band at a time), not used often, receiver synchronized with transmitter
DSSS: Whole chunk, multiple bands at once
OFDM: Multiple bands together, better protection from RF
What are the types of antennas?
Omni-directional (dipole), semi-directional (yagi, patch), Parabolic Grid
What does an omni-directional antenna do?
Home router - can be oriented different directions, weak signal spots above and below antenna
What does a semi-directional antenna do?
Yagi: Long, horizontal, transmits in one direction, requires precision pointing (fixed point to point)
Patch: flat surface, wider transmission, point to point or multi point
What does parabolic grid do?
Many directions, long distance point-to-point, (Teta’s satellite)
What is open authentication?
No security, anyone can connect, requests IP address
What is WEP?
Wired Equivalent Privacy - encrypted but not secure any more
What is WPA?
Wireless Protected Access - increased protection. Pre-Shared Key (PSK) exchange and 4-way handshake
What does TKIP stand for?
Temporal Key Integrity Protocol - 128-bit key for each packet
What is WPA2?
Enhanced security WPA, not interopable with WPA, uses AES (Advanced Encryption Standard) instead of TKIP
What is WPA-2 enterprise
Radius authentication - requires central database to authenticate users (infrastructure mode)
Why does 2.4 Ghz have more interference?
More common devices, like cordless phones?
What is MIMO?
essential part of wireless in, allows many connections in and out
What are the control plane and data plane?
Control plane manages channels, frequency and protocols, while data plan manages data, usernames and passwords
How do you secure a tunnel?
pre-shared key on both sides
