Monday, 19 September 2011

CCNA Wireless Tutorial and Questions

In this article we will discuss about Wireless technologies mentioned in CCNA.
Wireless LAN (WLAN) is very popular nowadays. Maybe you have ever used some wireless applications on your laptop or cellphone. Wireless LANs enable users to communicate without the need of cable. Below is an example of a simple WLAN:

Each WLAN network needs a wireless Access Point (AP) to transmit and receive data from users. Unlike a wired network which operates at full-duplex (send and receive at the same time), a wireless network operates at half-duplex so sometimes an AP is referred as a Wireless Hub.
The major difference between wired LAN and WLAN is WLAN transmits data by radiating energy waves, called radio waves, instead of transmitting electrical signals over a cable.
Also, WLAN uses CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) instead of CSMA/CD for media access. WLAN can’t use CSMA/CD as a sending device can’t transmit and receive data at the same time. CSMA/CA operates as follows:

+ Listen to ensure the media is free. If it is free, set a random time before sending data
+ When the random time has passed, listen again. If the media is free, send the data. If not, set another random time again
+ Wait for an acknowledgment that data has been sent successfully
+ If no acknowledgment is received, resend the data

Question 1
Which additional configuration step is necessary in order to connect to an access point that has SSID broadcasting disabled?
A. Set the SSID value in the client software to public.
B. Configure open authentication on the AP and the client.
C. Set the SSID value on the client to the SSID configured on the AP.
D. Configure MAC address filtering to permit the client to connect to the AP.

Answer: C
Question 2
What is one reason that WPA encryption is preferred over WEP?
A. A WPA key is longer and requires more special characters than the WEP key.
B. The access point and the client are manually configured with different WPA key values.
C. WPA key values remain the same until the client configuration is changed.
D. The values of WPA keys can change dynamically while the system is used.

THERE ARE LOT OF QUESTIONS
For more questions please visit :http://padegaindia.in/2011/09/ccna-wireless-tutorial-and-questions

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