Wireless routing

Question 1

802.11b WLAN routing protocol

Answer 1

• most widely deployed wireless standard
• operate at 2.4 ghz radio ban 11mps data rate
• has the ability to data-rate-shift while moving, and transmission by transmission basis
  -means access point an support multiple clients at varying speeds
  -uses CSMA?CA and Request to send, clear to send (RTS?CTS)
  Has interference

Question 2

802.11g

Answer 2

-backwards compatable with 802.11b
- 54mbps max data rate
- runs on 5 + 2.4 ghz range
can communicate on same network
uses module technique called OFDM- better performance at same rate
gets 70% of RF bandwidth

Question 3

Wifi channels for 802.11g

Answer 3

11 configurable channels

• 1,6,11- non overlapping
• must be aware of channels when installing AP to not overlap channels

Question 4

802.11a

Answer 4

-5ghz
can data rate shift
- 12 non-overlapping channels
immune to interferences eg microwave, Bluetooth

Question 5

802.11h

Answer 5

5ghz
FCC added 11 channels
gained 23 non-overlapping channels

Question 6

Dynamic frequency selection (DFS)

Answer 6

• monitors a device operating range for any radar signals allowed to operate in 5ghz proportions
• if dfc discovers radar signals it will either: abandon channel, mark it unavailable to prevent interference

Question 7

Transmit power control (TPC)

Answer 7

• employed by the mobile phone industry

- can set client machine adapter + access point to cover various size ranges

Question 8

Radio frequencies

Answer 8

go straight with signal

• if anything blocking hard to send signal
• can lose all or part of a signal

Question 9

Reflection

Answer 9

the signal bounces off material that cant absorb the signal
objects can scatter signal
-

Question 10

Wireless degredation

Answer 10

• factors that interfere with RF (Radio frequency)

Question 11

what is fading?

Answer 11

signal weakening due to reflection

Question 12

Attenuation

Answer 12

signal weakening due to distance

can correct with an extender

Question 13

noise

Answer 13

interference from other devices

common due to unlicensed spectrum

Question 14

wireless fidelity

Answer 14

devices communicate directly
- communication managed through wireless access points
-WAPS may interoperate to provide large seamless coverage
max distance 300 ft station with wap
max distance b/w waps 1000ft w/ antenna

Question 15

Antenna types

Answer 15

omni directional

unidirectional

Question 16

what is omnidirectional antenna type

Answer 16

the signal transmitted in all 3 directions equally

Question 17

Uni directional

Answer 17

signal transmitted in one direction

typically used to gain range

Question 18

Wifi identifiers

Answer 18

-Service set identifier (SSID)
-\basic service set identifier (BSSID)
Basic service set (BSS)
Extended servce set identifier (ESSID)

Question 19

Extended servce set identifier (ESSID)

Answer 19

WLAN name that spans many BSS’s

same WLAN name as SSID

Question 20

Basic service set (BSS)

Answer 20

A wap and all stations communicating with it

Question 21

-basic service set identifier (BSSID)

Answer 21

one for each WLAN for each radio on WAP using mac address

wap typically has many bssid’s

Question 22

-Service set identifier (SSID)

Answer 22

WLAN IDENTIFIER

may be more than one a wap

Question 23

Wireless standard frequencies

Answer 23

802. 11b 2.4 ghz - max throughput- 11mbit/s
803. 11g 2.4 ghz - max throughput- 54mbit/s
804. 11n 5+ 2.4 ghz - max throughput- 150mbit/s