Friday, 21 August 2015

802.11 + WLAN Driver + OpenWRT training sessions

Teaching is fun :).  I have started teaching few little things that I know about WLAN to a bunch of enthusiastic students who want to pursue their career in WLAN / OpenWRT domain. We have 10+ students in this batch.

It is almost 4 weeks since we started.  We have started with the discussion of TCP/IP Stack and then moved to Linux process model and socket programming. We will conclude our discussion on socket programming tomorrow.

Securifi has kindly permitted to use their conference rooms for the training sessions. 

We use MT7620a based boards for all our training sessions and projects.

 Following is the list of topics that we are planning to discuss further.

 - OpenWRT architecture
        - Architecture overview
        - Package model
        - How to flash a router
        - How to add a new package
        - UCI
        - LUA and LUCI

 - 802.11a/b/g/e/n protocols
        - CSMA/CA
        - RTS/CTS
        - Hidden Node problem
        - State Machine 
        - Frames and frame format
        - Powersave, UAPSD
        - Aggregation
        - Fragmentation
        - Outdoor WiFi 
        - WEP, WPA and WPA2

 - Device drivers in Linux covering the following.
       - Introduction to Kernel level programming
       - Linux Kernel Module
       - Locking Techniques
       - Kernel Memory
       - Tasklets, Interrupts, Timers
       - Memory mapped IO, Port IO, DMA in Linux
       - Network driver concepts
       - Character driver

 - WLAN driver
        - Overview of ath9k driver
        - Tx and Rx Paths
        - Important data structures in mac80211
        - Communication between cfg80211, nl80211, mac80211 and ath9k
        - hostapd and wpa_supplicant

Drop an email to me at if you would like to join.

Saturday, 11 July 2015

OpenWRT WiFi Configuration Flow

LUCI is the most popular Web UI Interface available to configure OpenWRT based router. How the wireless settings are percolated down till driver level when you apply the settings from from Web UI via LUCI . They say "A picture is worth a thousand words" :) .  I tried to make a simple picture. Hope it really is worth of atleast few words :)


Thursday, 5 February 2015

Alternate firmware for UniFi APs

Today we have released "Alternate firmware for UniFi APs". You can download the firmware from,

Along with providing basic wireless Access Point services, it offers the following features.

1. Social WiFi network - Ability to authenticate the wireless clients using Facebook login credentials
2. Uplink Connectivity - You can just install the "Nearhop powered AP" into your network without connecting it through wires. You just need to specify the details (ssid, keys etc) of your already existing AP. Uplink connectivity feature can be used as repeater or range extender or client bridge upto any number of hops
3. Router Mode: This mode makes the device as a router
4. OpenVPN: OpenVPN client is supported
5. Statistics of wireless clients including the name, email id, transmitted bytes, received bytes and browsing history of each user
6. Send email from the router itself to all the connected users
7.  RF-Analysis - Highly useful in finding out the best wireless channel  to operate

Try this firmware and don't forget to email your feedback  to