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CWAP – 802.11 Mgmt Frame Types
802.11 Management Frames have MAC header with 3 addresses fields in it. If it is 802.11a/b/g then it has 24 byte MAC header where as if it is 802.11n management frame it has 28 byte (additional 4 byte...
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CWAP – 802.11 Control Frame Types
802.11 Control Frames assist with the delivery of Data & Management frames. Unlike management & data frames, Control frames does not have a frame body. The type (always 1 for control frames)...
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CWAP – MAC Header : QoS Control
QoS Control is a 16-bit field that identifies the Quality of Service (QoS) parameter of a data frame (only in data frame type QoS-Data).QoS Control field is comprised of five subfields 1. [bit 0-3 ]...
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My CWAP Study Notes
In this post I am going to summarize my CWAP (Certified Wireless Analysis Professional) notes. Like any other CWNP exam, this also has 70% passing mark & exam objective is shown as below with their...
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802.11ac with 3850 & 3702
In this post we will see 802.11ac performance using a 3702 with a Cisco 3850 WLC. I have used two 802.11ac clients (Samsung Galaxy S5 & Dell E7440 with Intel AC7260 NIC). Here is my topology for...
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802.11 Mgmt : Beacon Frame
Beacon frames are used by the access points (and stations in an IBSS) to communicate throughout the serviced area the characteristics of the connection offered to the cell members. This information...
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802.11 Mgmt : Action Frames
Action Frames are a type of management frame used to trigger an action in the cell. Action frame format is as shown below Category – Describes the action frame type. Here are the different category...
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802.11 Mgmt : Authentication Frame
Once a client station is discover a SSID (Probe Request/Response or listening to Beacons) it move to Join phase. This exchange comprise of at least 4 frames 1. Authentication (Request) 2....
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802.11 Mgmt : Deauth & Disassociation Frames
Deauthentication Frame Station or AP can send a Deauthentication Frame when all communications are terminated (When disassociated, still a station can be authenticated to the cell). Deauthentication...
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CWAP – 802.11 Medium Contention
DCF- Distributed Coordination Function : Non-QoS WLAN HCF with EDCA – Hybrid Coordination Function : QoS WLAN EDCA- Enhanced Distributed Channel Access PCF – Point Coordination Function (not...
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CWAP – 802.11 Data Frame Types
There are 15 different types of Data Frames defined in IEEE 802.11-2007 standard. Data frames with a value of 1 in the QoS subfield of the Subtype field (Bit7) are collectively referred to as QoS data...
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CWAP – 802.11 Power Management
A wireless radio can perform one of the 4 activities. Power consumed by each activity increases in the given order ( 1-4). 1. Asleep 2. Idle & awake 3. Receiving 4. Transmitting There are 3 methods...
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CWAP 802.11 PHY – PPDU
802.11 Physical (PHY) layer is divided into two sublayers 1. PLCP (Physical Layer Convergence Procedure) sublayer 2. PMD (Physical Medium Dependent) sublayer The PLCP prepare the frame for transmission...
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CWAP – 2.4GHz vs 5GHz
2.4GHz (2.4000 GHz to 2.4835 GHz) - 802.11 (FHSS clause 14 or DSS clause 15 radios) – 802.11b (HR-DSSS clause 18 radios) – 802.11g (ERP clause 19 radios) – 802.11n (HT clause 20 radios) In addition to...
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WLC Client Debug – Part 1
When you are troubleshooting wireless client connectivity issues there is a one command you always need to use. “debug client <client_mac_address>” output will tells you what’s going on. To...
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CWAP – Spectrum Analysis
WiFi Spectrum Analyzer considerations – Frequency – Form factor – Price – Hardware Platform – Resolution – Supporting Software – WiFi integration Free Space Path Loss(FSPL) FSPL isthe loss of signal...
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WLC Client Debug – Part 2
In this post we will see how to utilize “debug clinet x.x.x.x” output to understand the process a wireless client go through get connected to WPA2-PSK configured wireless network. Here is the basic...
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CWAP – 802.11n Introduction
802.11n-2009 (HT-Clasue 20) amendment was ratified on September 2009, essentially a list of enhancement to improve the performance & throughput of 802.11a/g standards. PHY Layer enhancements 1....
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CWAP – HT Capabilities IE
802.11n introduces 4 new information elements which can be seen in 802.11n (HT) beacon frames. HT STAs declare themselves as HT STA by transmission of HT Capabilities Element in Beacon, Probe Request,...
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CWAP – HT Control Field
The 802.11n amendment add a 4 byte HT control field to the 802.11 MAC header. With this HT Control field max MAC header length increased to 36 bytes. HT Control Field is always present in a Control...
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