ROC III, Course II, Lessons 1-4
Which of the provided voltage standing wave ratios (VSWR) shown here is best for transferring radio frequency (RF) energy between connections?
1.2:1
The Federal Communications Commission (FCC) rules regarding power output for frequency-hopping spread spectrum (FHSS) state that a maximum output to the intentional radiator (IR) with 5 megahertz (MHz) of carrier frequency bandwidth must be which one of the following?
125 milliwatts (mW)
A transmitter outputs 100 milliwatts (mW). An antenna cable connects the transmitter to an amplifier, and the power into the amplifier's input measures 50 mW. The amplifier increases the signal to the original transmitter's power level and sends the signal to the antenna. The antenna receives the signal from the amplifier at 75 mW, and then transmits at 150 mW. What is the intentional radiator's (IR) power level in this radio frequency (RF) circuit?
75 mW
Which of the following Institute of Electrical and Electronics Engineers (IEEE) 802.11 wireless local area network (WLAN) standards specifies both spread spectrum radio frequency (RF) and infrared (IR) transmission technologies?
802.11
Which one of the following Institute of Electrical and Electronics Engineers (IEEE) wireless standards utilizes the 5 gigahertz (GHz) frequency band for its signal transmissions?
802.11n
Which statement best describes protocol filtering that has been implemented in a wireless bridge?
Allowing or denying wireless traffic using Open Systems Interconnection (OSI) reference model Layer 4 (Transport Layer) ports to filter Layer 7 (Application Layer) applications.
What is the width of direct sequence spread spectrum (DSSS) channels and how far apart are their center frequencies spaced?
22 megahertz (MHz) wide and 5 MHz apart
What security service in an enterprise wireless gateway enables the wireless network administrator to assign levels of service to a particular user?
Class of service (CoS)
What unit of measurement is used to express the gain of an antenna?
Decibels isotropic (dBi)
Although there are many different implementations of spread spectrum technology, what are the only types specified by the Federal Communications Commission (FCC) in the Codes of Federal Regulation (CFR), Volume 47, Part 15?
Direct Sequencing Spread Spectrum (DSSS) and Frequency Hopping Spread Spectrum (FHSS)
What specific problem does a wireless local area network (WLAN) resolve for corporations and home users?
Excessive data cabling
In what manner do radio waves propagate (move) away from the source (antenna)?
In a straight line in all directions at once
What type of connectivity is needed to connect networks between two buildings located across the street from each other?
Point-to-point (P2P)
How does radio frequency line-of-sight (RF LOS) differ from visual LOS?
RF LOS is accompanied by a Fresnel zone, a series of concentric ellipsoid-shaped areas around the visual LOS path
In which Open Systems Interconnection (OSI) reference model layer do wireless local area networks (WLAN) operate?
The Data Link Layer
What is Equivalent Isotropically Radiated Power (EIRP)?
The power actually radiated by the antenna element
In a frequency-hopping spread spectrum (FHSS) system that uses 10 frequencies across a 12 megahertz (MHz) frequency band, what happens if narrowband interference occurs at only one of the 10 frequencies?
The spread spectrum signal remains intact. Instead of being lost, the data on the interfered frequency is retransmitted on one of the other nine frequencies
What are some measures that can be taken to prevent high voltage standing wave ratios (VSWR) in transmitters and receivers?
Tighten connections between cables and connectors and use impedance-matched hardware throughout
Why are wireless local area networks (WLAN) usually deployed in an access capacity instead of as the network's core layer?
WLANs are generally incapable of meeting the requirements of the network core layer, which needs to be very fast and stable, able to handle a tremendous amount of traffic with little difficulty, and must experience no down time
Residential gateways have been around for quite some time, but what capability was added to connect to Institute of Electrical and Electronics Engineers (IEEE) 802.11b-, 802.11g-, 802.11n-, and 802.11ac-compliant devices?
Wireless capability.
What is a half-duplex device that is only capable of Open Systems Interconnection (OSI) reference model Layer 2 (Data Link Layer) connectivity?
A wireless bridge
What are some common methods used to configure and manage access points (AP)?
Telnet/ssh (secure shell), universal serial bus (USB), and a built-in web server for browser access
Given an access point (AP) with 100 milliwatts (mW) of output power connected through a cable with 3 decibels (dB) of loss to the antenna with a 10 decibels isotropic (dBi) gain, what is the approximate Equivalent Isotropically Radiated Power (EIRP) level from the antenna in mW?
500 mW
What wireless local area network (WLAN) device can be described as a half-duplex device with intelligence equivalent to that of a sophisticated Ethernet switch?
An access point (AP)
In which of the following applications might a wireless local area network (WLAN) be deployed in a distribution layer role?
As a building-to-building bridge used to link corporate network segments
What challenges do Wireless Internet Service Providers (WISP) have to overcome in order to provide "last mile data delivery" to customers?
Distance to access points (AP), rooftop access, lightning, trees, mountains, tower access, and other physical obstacles to connectivity
The ratio of the chipping code to data bits for a direct sequence spread spectrum (DSSS) signal is called which of the following?
Processing gain.
Which one of the following radio frequency (RF) behaviors is defined as "the bending of a wave as it passes through a medium of different density"?
Refraction
You are designing a wireless network to which several functional workgroups are connected. You want to configure your enterprise wireless gateway to allow you to quickly assign identical network access rights to persons within the same workgroup. Which enterprise wireless gateway feature provides this capability?
Role-Based Access Control (RBAC)
Why is the Fresnel zone important to the integrity of the radio frequency (RF) link or path?
The Fresnel zone defines an area around the RF line-of-sight (RF LOS) that can introduce RF signal interference if blocked
Why has it become cost-effective for enterprise companies to integrate wireless local area network (WLAN) segments into their networks?
The cost of wireless technology has decreased and the quality has increased.
Why should a wireless network administrator consider installing an enterprise wireless gateway in their network?
The enterprise wireless gateway enables the wireless network administrator to manage a large wireless network using only a few central devices instead of a very large number of access points
Which component of frequency hopping spread spectrum (FHSS) system creates more overhead than any similar component in a direct sequence spread spectrum (DSSS) system?
The interframe spacing
Which wireless client devices require drivers to be installed on the client node?
Wireless client devices on printed circuit (PC) cards that are to be installed in peripheral component interconnect (PCI) or industry standard architecture (ISA) adapters
Which of the following networks or products use spread spectrum technologies?
Wireless local area networks (WLAN), Bluetooth, and global positioning systems (GPS)
How does spread spectrum technology reduce the probability of signal jamming?
By transmitting over a wide frequency spectrum
Why is direct sequence spread spectrum (DSSS) the most widely known and the most used of the spread spectrum types?
Its ease of implementation and high data rates
Why is spread spectrum technology used in applications such as Bluetooth wireless personal area networks (WPAN)?
Spread spectrum technology allows wireless networking to create a short range, personal communications network.
Which organization regulates the use of wireless local area network (WLAN) devices in the United States?
The Federal Communications Commission (FCC)
Which statement best describes a network application for which a wireless workgroup bridge is the best suited?
When remote buildings house small groups of wired clients needing wireless access to the main network
