Saturday, 26 May 2018

802.11 Roaming Variations Cheatsheet

I recently saw a very interesting post from Gjermund Raaen about Fast Secure Roaming, where he discusses OKC and 802.11r. This reminded me of some roaming issues I had recently observed with OKC myself, which got me looking up information to refresh my memory on a variety of roaming methods and standards.

While looking in to the issue, I came across a classic blog post from Andrew Von Nagy about 802.11 roaming. It provides a superb summary of various roaming and security methods. I've read the post several times in the past, but thought that I would really benefit from a summary of its content to act as a memory jogger, rather than reading through the whole document again. For me, things get a little hazy when I start trying to remember the intricacies of the differences between EAP session resumption, PMK caching, OKC and PMK.

To save myself some time for the next time I go through this loop, I put together a summary (Cheatsheet) of the content of the roaming variations post. If you'd like to get a copy of the sheet, please feel free to download it yourself: 802.11 Roaming Variations

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Sunday, 20 May 2018

Updated White Paper on Licence-Exempt Spectrum in the 5GHz band for Wireless LANs in the UK

For the past few years, I've maintained a white paper on the use of the 5GHz spectrum for Wi-Fi networks here in the UK. As Wi-Fi text books tend to focus on the spectrum available in the USA, I put this document together to clarify how 5GHz spectrum may be used in the UK.

Following the release of a Voluntary National Specification document by Ofcom in August 2017 (VNS 2030/8/3), additional channels became available for use in the UK on 5GHz.

As we now have additional spectrum, it's time for an update to my white paper to detail the new spectrum that is available.

Prior to updating the white paper, I published a summary sheet that shows the new spectrum allocation. This can be obtained obtain from my previous blog article: UK 5GHz WLAN Spectrum Allocation (August 2017) (this is definitely one to print off and laminate).

I have now completed my updates to the white paper, which I am pleased to share with you now. Note that in addition to adding the new spectrum details, I have added a few other topics around the use of 5GHz and the unique challenges that it presents. I'd recommend taking a look at my description of how DFS operates in Appendix 2, and have a play with the Opera weather radar location tool shown in Appendix 3.

I hope you find the update useful and informative.

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Saturday, 21 April 2018

Scapy 802.11 Cheat Sheet

I've been taking a look at Scapy as I've been learning more about Python. It's a great Python-based tool for capturing, analyzing and creating network packets. There are some great resources to learn more bout Scapy, and even some cheat sheets out there.

But, as there were quite a few new concepts (for me) and my own interest is in Scapy for 802.11 related activities, I put together my own Scapy for 802.11 cheat sheet. You can grab a copy from here if it may be useful to you.

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