CWAP – Monorail

I passed CWAP-403 and CWDP-303 few days ago. It has been a very rewarding study, but long and tiresome. I rushed to take the certifications before my study guides and practice tests expired at the end of October, and passed at first attempt.

CWAP is hard. I used the 2011 Wiley CWAP Study Guide as a foundation, then Matthew Gast 802.11ac Survival Guide, and the official CWAP-403 Study Guide. I did many packet captures and analysis, but the most useful inspiration and motivation came from following the WLAN community.

The practice tests were very valuable to gauge my readiness and motivate me taking the exam at last.

CWDP is often overlooked as an easy certification, perhaps because many people take it when they’re already advanced in the WLAN learning path. I used CWDP study for taking guilt-free breaks during the preparation of CWAP and it worked well for both certifications in the end.

I used the official Study Guide and the practice tests, but the real factor in passing this exam was the experience built up in my job as WLAN administrator and designer at my university.

Now I’m looking forward what to do next. On the cert/study line, an IoT exam like CWISA. Writing more on the blog, and giving back to the WLAN community, maybe by doing something local here in Europe/Italy.

The Sybex CWAP 2011 study guide contains a gem regarding how different BSSs interact:

[with the exception of transmitter and receiver,] Any other client or AP stations within hearing range on the same channel will reset their NAV, even if they are nont members of the BSS.
Chapter 3 review questions, q.10, answer p.120

It is the first time I find it clearly stated that STAs contending through HCF or EDCA will abide to any information they can decode from received frames, regardless if they are from the same BSS or not.

This makes sense, because:

APs know the AID of the members of it’s BSS, but client STA don’t;
any STA (AP or client) does physical carrier sense SD when it decodes a preamble, and it is likely to also decode the header which contains a length field which is the time it will take to transmit the frame (in microsecs);
Therefore it’s logical to use a NAV if it can decode it.

Perhaps this should be put in the CWNA study guide explicitly.