CWNA MATERIALS

[affolly]

I WILL BE GOING FOR MY CWNA EXAMS NEXT WEEK, PLEASE GROUP MEMBERS SEND
ME MATERIALS FOR MY LAST MINUTES PREPARATIONS.

THANKS.

[Eric Vanderburg]

We do not offer test questions or anything but we will be happy to
answer questions you have about wireless networking. If you are
looking for sample questions, there are many reputable web sites that
can sell you some. Stay away from braindumps as those are not only
cheating but they will not help you understand the technology and they
often contain errors. Is there an area in which you are having
trouble?

- Eric Vanderburg
Network Operations Manager
JurInnov, Ltd.

Adjunct Professor of Computer Information Systems
Lorain County Community College

[Eric Vanderburg]

Prashant,

 

Thanks for asking your wireless questions. 

 

1. Why Wi-Fi is working on Half duplex?

 

In order for a medium to be full-duplex there has to be a portion of the medium allocated to sending and another to receiving.  Cables such as CAT5 use some wires for transmitting and others for receiving.  RF frequencies carry only one signal at a time so the transmissions are inherently half-duplex. 

2. What is differnce between Virtual carrier sence & Physical
carrier sense ?

 

802.11 uses CSMA/CA.  This is a bit different from CSMA/CD used in Ethernet networks in that there is a lot more traffic used to prevent collisions.  In this topology nodes will do a carrier sense to determine whether or not the medium (RF band) is busy or not.  The two methods you mentioned are the ways a wireless node will do this. 

 

Virtual carrier sense is termed virtual because it operates on layer 2 by analyzing frames and using logic to determine when it is free to transmit rather than simply watching for RF signals on the wireless medium.  This logic makes use of a value called a NAV (Network Allocation Vector).  A station will not transmit when its NAV is greater than 0.  The NAV is decrimented by one each microsecond and updated when new information on the duration of existing communication on the network is obtained.  This information is obtained as the node examines the Duration/ID field in the MAC header of all unicast frames it receives. The Duration/ID contains either an ID or a duration that represents an estimation of the amount of time in microseconds it will take for the receiving station to receive the frame and respond with an ACK.  The wireless node then takes this duration value, if it is in the frame, and stores it in its NAV replacing the current NAV value.  (CWNA Guide pg. 224-225)

 

As alluded to before, physical carrier sense consists of a node monitoring the RF medium for RF signals. 

 

3.  What study materials should you use?

 

The first resource you need is the CWNA Study Guide 4th ed. (ISBN: 978-0-07-149490-8) which I referenced above.  Other group members have also provided a number of links to good web sites.  You can find those links if you seach through some of the posts in this group.  

 

I hope that helps.  

 

- Eric Vanderburg

 

On Sat, Oct 4, 2008 at 2:37 AM, Prashant <prashant...@gmail.com> wrote:

Dear Eric,

 I am Prashant & Looking for CWNA certification.

 Can you please guide me how to start & which books should I refer??

 Please suggest I have some basic doubts

 1. Why Wi-Fi is working on Half duplex?
 2. What is differnce between Virtual carrier sence & Physical
carrier sense ?

 Can you please suggest/Guide me.

On Dec 20 2007, 7:03 am, "Eric Vanderburg" <evanderb...@gmail.com>

[Prashant]

Dear Eric,

Thanks for the basic information. As per your suggestion I ref. 4th
edition book & finally I have completed by CWNA certification.

Now I am looking for CWSP so do you have any good material for this.

How should I proceed for this kindly suggest.

> (*ISBN:*978-0-07-149490-8) which I referenced above.  Other group

> > > Lorain County Community College- Hide quoted text -
>
> - Show quoted text -

[Eric Vanderburg]

Prashant,

Congratulations on passing the CWNA exam. What a great achievement.
The CWSP is an excellent next goal and a difficult test. It is
essential to have the official CWSP exam guide and I would also
recommend Wi-Foo: The Secrets of Wireless Hacking. This book was an
excellent reference for me. I have the first edition but there is a
second edition now. There are other books I recommend as you continue
to learn about wireless security and penetration testing.

Here is what I would consider my Wireless security book list:

WiFoo (1st Ed.) ISBN 0321202171 or
WiFoo (2nd Ed.) ISBN 0321393716
Hacking Exposed Wireless ISBN 0072262583
Guide to Wireless Network Security ISBN 0387954252
Cisco Wireless LAN Security ISBN 1587051540
Wireless Network Security ISBN 0387280405
Wireshark & Ethereal ISBN 1597490733
Wardriving & Wireless Penetration Testing ISBN 159749111X
Linksys WRT54G Ultimate Hacking ISBN 1597491667

Eric Vanderburg
Network Operations Manager
JurInnov, Ltd.

Adjunct Professor of Computer Information Systems
Lorain County Community College

[Eric Vanderburg]

Prashant,

What kind of work do you do? Are you looking for a different career
direction by becoming a certified wireless professional?

- Eric Vanderburg

[Prashant]

Dear Eric,

Can I get CWSP Official Study Guide softcopy anywhere on Internet??

Please suggest.

On Oct 27, 4:40 pm, "Eric Vanderburg" <evanderb...@gmail.com> wrote:
> Prashant,
>

> >> > - Show quoted text -- Hide quoted text -

[Eric Vanderburg]

Amazon has one for the kindle.
http://www.amazon.com/Certified-Wireless-Security-Professional-Official/dp/B001EO6YTW/ref=sr_1_3?ie=UTF8&s=books&qid=1225988717&sr=8-3

I did not see ebooks anywhere else.

- Eric

[Prashant]

Hi Eric,

Wish You Very Happy New Year.

On Nov 6 2008, 10:03 pm, "Eric Vanderburg" <evanderb...@gmail.com>
wrote:
> Amazon has one for the kindle.http://www.amazon.com/Certified-Wireless-Security-Professional-Offici...

[Eric Vanderburg]

Thanks. Happy New Year to you as well and to everyone in the CWNP group.

- Eric Vanderburg