new ccna format

new ccna format.22. which type of multiplexing technology does 802.11n use?a. spatial multiplexing b. OFDM c. DSSS d. FHSS 23.In an 802.11n network, what task is accomplished by TxBF?a. transmits signals on multiple transmit antennas to improve performance at the receiver b. enhances signals to transmit over longer distances c. signals are propagated over multiple channels and then reconstructed at the receiver to eliminate interference problems on the sidebands d. binds signals to 40 MHz channels to provide more bandwidth24. How does 802.1111 use acknowledgement to increase throughput?a. Use 1-to-1 acknowledgement answer option § 1 send = 1 acknowledgement answer b. Do not use acknowledgements c. Use blocking acknowledgementsd.Use 2-to-1 transmit frames for acknowledgement 25.Which of the following devices has two transmit antennas and two receive antennas?a. DualTxRx b. 2X2 c. 2x d,Adouble6.2 Basic Topics6.2.1802.11 Protocol Family Overview IEEE promotes the standardization of wireless protocols. For the CCNA Wireless certification exam, you must be proficient in the 802.11a/b/g and 802.11n protocols. These four IEEE standards define the family of wireless protocols used in almost all of today's WLANs. The standardization of wireless networking began with the initial 802.11 protocol in 1977, and each subsequent protocol simply added something that benefited wireless technology. This chapter describes the 802.11 protocol family, its history, and how these protocols work. The 802.11 protocols operate at 2.4GHz and 5GHzo6.2.2 Initial 802.11 Protocols Initial The 802.11 protocol is the beginning of WLANs. This initial protocol is rarely seen anymore in today's new hardware, probably related to the fact that it only works at IMbit/s and 2Mbit/s rates. The 802.11 standard describes Frequency-Hopping Spread Spectrum (FHSS) technology, which operates only at IMbit/s and 2Mbit/s. The standard also describes Direct Sequence Spread Spectrum (DSS) technology, which operates at IMbit/s and 2Mbit/s rates. The standard also describes the Direct Sequence Spread Spectrum (DSSS) technique, which also operates only at