CompTIA Network+ N10-006 Q139

A company is deploying a new wireless network and requires 800Mbps network throughput. Which of the following is the MINIMUM configuration that would meet this need?

A. 802.11ac with 2 spatial streams and an 80MHz bandwidth
B. 802.11ac with 3 spatial streams and a 20MHz bandwidth
C. 802.11ac with 3 spatial streams and a 40MHz bandwidth
D. 802.11ac with 4 spatial streams and a 160MHz bandwidth

Correct Answer: A
Section: Industry standards, practices, and network theory

Explanation:
Spatial streaming is used in wireless communications where multiple-input-multiple-output (MIMO) is being used. With MIMO, multiple antennas are used for transmission and reception. MIMO was available in 802.11n but its capabilities have been extended in 802.11ac.
802.11ac supports a mandatory 80 MHz channel bandwidth for stations (vs. 40 MHz maximum in 802.11n), 160 MHz available optionally and more (up to 8) special streams.
A single antenna and 80 MHz channel bandwidth provides a bandwidth of 433Mbps. In this question, we need a minimum bandwidth of 800Mbps. Two antennas and 80 MHz channel bandwidth provides a bandwidth of 867Mbps and therefore meets the requirement.