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CWSP RELEASE DATE 2/08/2010
  • CWSP Certified Wireless Security Professional Official Study Guide: Exam PW0-204
    CWSP Certified Wireless Security Professional Official Study Guide: Exam PW0-204
    by David D. Coleman, David A. Westcott, Bryan E. Harkins, Shawn M. Jackman

    Shawn Jackman (Jack) CWNE#54 is a personal friend and has been a mentor to me for many years.  I've had the pleasure and opportunity to work with Jack for 4 years. Jack is a great teacher who takes complex 802.11 standards and breaks them down so almost anyone can understand the concept at hand. I'm excited for you brother. Great job and job well done! Put another notch in the belt!

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IEEE 802.11a/g/n Reference Sheet

 

« "Wi-Fi doesn't stand for anything. It is not an acronym. There is no meaning.” | Main | Cisco 8.0 MR3 Beta Open to Public »
Monday
Jan252016

802.11 - TIM and DTIM Information Elements  

In this blog post I investigate 802.11 TIM and DTIM.

Read the entire blog post here: 

http://community.arubanetworks.com/t5/Technology-Blog/802-11-TIM-and-DTIM-Information-Elements/ba-p/256997 

Traffic Indication Map (TIM) - 

After reviewing what the 802.11 standard says about TIM. Lets discuss in real world terms what a TIM is and how it works. 

You will specifically find TIM in a management frame called a beacon. A beacon is triggered by default on an access point every 102us. Think of a beacon as a network advertisement. The beacon advertises specific <BSSID> wireless network information such as supported PHY rates, security protocols, supported QoS/WMM, vendor specific information and much much more. Included in the beacon is a TIM information element. 

Example: BEACON WITH TIM

Delivery Traffic Indication Map (DTIM) - 

After reviewing what the 802.11 standard says about DTIM. Lets discuss in real world terms what a DTIM is and how it works. 

You will specifically find DTIM in a management frame called a beacon under the TIM information element. DTIM is to broadcast / multicast traffic as TIM is to unicast traffic.

Under the TIM you will see DTIM count and DTIM period. 

Example: DTIM COUNT / DTIM PERIOD 

 

 

 

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