Q: 1
Which IEEE 802.11 physical layer (PHY) specification includes support for and compatibility with both
ERP and HR/DSSS?
Options
Discussion
Option C The catch is it only holds if we're talking about 2.4 GHz compatibility, since 802.11n (HT) supports both ERP and HR/DSSS in that band. Switch the context to just 5 GHz and this wouldn't be true. Happens a lot with legacy support questions from what I see on practice sets.
C tbh, 802.11n (HT) is the only spec here that covers both ERP and HR/DSSS compatibility in the 2.4 GHz band. OFDM and VHT just don't provide backward compatibility like that. I think this question's really about legacy device support so C fits best, unless there's a band twist I missed.
C makes sense here since 802.11n (HT) adds backward compatibility with both ERP and HR/DSSS, but only in the 2.4 GHz band. OFDM or VHT don't support both of those older PHYs. Pretty sure this is what most practice tests are getting at, unless the question wants to trip you up on band specifics. Anyone see it worded differently?
B, Check the official study guide and some practice tests for IEEE PHY compat questions like this.
Option C
Honestly, I'd pick D. VHT is newer and thought it was backward compatible with the others.
Its C
C imo. 802.11n (HT) was specifically designed to be backward compatible with older 2.4 GHz devices (ERP and HR/DSSS). Nice clear question for anyone who’s reviewed the standards closely. Pretty sure on this, though always double check specs!
Totally C here. 802.11n (HT) supports both ERP and HR/DSSS for backwards compatibility, but only if you're in the 2.4GHz band. B doesn't work since 802.11a was strictly 5GHz. Unless I'm missing a detail, that's it.
Why not B? Pretty sure 802.11a (OFDM) had some compatibility for older PHYs too in certain scenarios.
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