Wednesday, May 27, 2009 Wednesday, May 27, 2009 10:41 PM
1.What are the standards belongs to unlicensed band?
802.11a / b/ g.

2.Which frequency band support 802.11b?
2.4GHz ISM band between 2.4000 & 2.4835GHz.
ISM = Industrial, Scientific and Medical

3.How to configure encryption in Access Point(AP)?
WEP .

4.What are the data rates offered for DSSS? FHSS?
DSSS- 1,2,5.5 and 11 Mbps
FHSS- 6.12.18.24.36.48 and 54Mbps

5.What kind of computer cannot use wireless LAN?
Rack-mounted computers

6.Which group of ISP provide Last Mile Data Delivery?
WISP

7.What is the main role for wireless LAN?
Access role.

8.Which standard belong to IEEE family?
802.11.

9.Building to building function must be provided by which NW devices?
wireless bridges
10.Which is the latest approved wireless standard from IEEE?
802.11g. If not ~g, then ~a.

11.DSSS can have max. of how many AP?
2

12.Peer to peer is always refers to what mode?
Ad Hoc Mode

13.What is the long form for SSID?
Service Set Identifier.

14.What is the usage of SSID?
it is for the client to authenticate and associate to the service set.

15.What is the data rates for 802.11a? 802.11b? 802.11g?
802.11a- 54 Mbps
802.11b- 11 Mbps
802.11g- 54 Mbps

16.What are the frequency rate used by wireless LAN?
2.4 – 2.5 GHz
5.725 - 5.875 GHz
5.15 -5.25 GHz
5.25 – 5.35 GHz
5.725 – 5.825 GHz

17.What are the frequency rate not used by wireless LAN?
5.36GHz - 5.724GHz are not use.
2 - 2.3 GHz
8 GHz...

18.What term to use when a client is able to move from cluster 1 of AP to another cluster of AP?
Roaming

19.What technology is used by GPS? WMAN? WWAM? WPAN?
Bluetooth --- WPAN
HiperLAN --- WLAN
MMDS, LMDS --- WMAN
CDMS, GPRS, GSM --- WWAN

20.In DSSS, what do you call the bit pattern as?
Chip or Chipping code.

21.In US, which organisation control the usage of wireless LAN?
Federal Communications Commission (FCC)

22.Why is FHSS better than DSSS?
Bluetooth uses FHSS and wireless uses DSSS, so FHSS offers better security than DSSS

23.What is wireless Residential Gateways? Give examples of application.
A wireless residential gateway is a device designed to connect a small number of wireless nodes to a single device for Layer 2(wired and wireless) and Layer 3 connectivity to the Internet or to another network.
Application is Small office and home office(SOHO)

24.What is the license-free radio frequency band? What is the bad points?
2.4 GHz that spans up to 6 miles under clear line of sight conditions.
bad point is that license-free radio frequency band will get possible random interference with other NW


25.What is the definition of wireless LAN?


26.What can affect the wireless LAN performance?
throughput, bandwidth, trueput.

27. What can affect the NW performance?
the placement of AP relative to clients, isolate from outside interference

[Short Answer Question]

27.Why do we want to use WLAN? <7>
Mobility
Installation Speed & Simplicity
Installation Flexibility
Reduced Cost-of-Ownership
Long-term cost benefits
Scalability
Configuration

28.What devices are needed to setup the wireless NW?
Wireless Network Interface Card
Access Point

29.What are the parameters we can use in AP settings?
mode,
SSID,
channel 1,
WEP,
....
MAC address filtering,
AP name,


30.What are the good points about using 802.11a WLAN? <5>
-802.11a is much faster data transfer rate than IEEE 802.11b
-802.11a uses the 5 GHz UNII frequency bands
-Able to achieve data rates of 6, 12, 18, 24, 36, 48 & 54Mbps
-The maximum data rate specified by the 802.11a standard is 54 Mbps

31.What are the bad points about using 802.11a WLAN? <5>
-It lacks backwards compatibility, the reaon is systems using 5 GHz frequencies will not communicate with systems using 2.4GHz

32.What is FHSS & DSSS stand for?
Frequency-hopping spread-spectrum (FHSS)
Direct-sequence spread-spectrum (DSSS)

33.What is the definition of FHSS & DSSS?
(FHSS) Uses a narrowband carrier that changes frequency in a pattern known to both transmitter and receiver.
(DSSS) Generates a redundant bit pattern for each bit to be transmitted.

34.What is WEP?
Wired Equivalent Privacy, a simple encryption algorithm that uses pseudo-random number generator (PRNG) and the RC4 stream cipher. It uses shared key authentication process for authenticating users.

35.What is bad about WEP?
BAD - it uses shared key cryptography, only 40 char length, initalisation vector can easily be broken