Forum

During my studies for the CWDP I've read (sorry can't find the pages right now) that open or CCMP is required for HT rates to be used (that's the info I currently thought was correct) and then it states in another page that it was a requirement from WFA but the ratified 11n does not require it anymore? What is the correct info?

Leonardo,

Good Question. I think the WFA does a little more than require it. I beleive they [u]forbid[/u] WEP at ant HT Rate.

An HT STA shall not use either of thte pairwise cipher suite selectos "Use group cipher suite" or TKIP to communicate with another HT STA.
Also..
An HT STA shall eliminate TKIP as a choice fo the pairwise cipher suite if CCMP is advertised by the AP of if the AP included an HT Capabilities element in its Beacon and Probe Response frames. So ..
The 80.11n-2009 definitely requires AP's to not use TKIP and even if they could the STA's could not. Not sure about WFA, but they generally are based off the IEEE standard.

Page 547 of the CWDP study guide is a little bit confusing and states:
"In other words, if you attempt to use open authentication or WEP the AP will default to only 802.11a/g data rates. This is a significant, though common, software problem that should have been updated with the final release of 802.11n"

It sounded like WEP had to be allowed with MCS rates.

Sorry for the confusion in the study guide. That will have to be updated in the next revision. The final 802.11n spec and the Wi-Fi Alliance are both clear in their intention to use CCMP (or open) for 802.11n communication. That remains consistent with vendor practices, which is to disable MCS rates if either WEP or TKIP are used for encryption between 802.11n stations.