Chapter 3 Review/ Guide to Networking Essentials Seventh Edition

c. 11 Note: 802.11b and 802.11g offer 14 channels, but only 11 can be used in North America.

How many channels can be used on an 802.11b network in North America? a. 7 b. 9 c. 11 d. 13

a. 802.11ac Note: 802.11ac—The 802.11ac standard was ratified at the end of 2013. It operates in the 5.0 GHz range only and continues to undergo development. Current implementations have data transfer speeds of about 1 Gbps, but future implementations will have speeds up to 6.93 Gbps.

Which Wi-Fi standard can provide the highest bandwidth? a. 802.11ac b. 802.11b c. 802.11n d. 802.11g

b. CSMA/CD Note: CSMA/CD is considered a contention-based access method, which means computers are allowed to send whenever they have data ready to send. CSMA/CD modifies this rule somewhat by stipulating that the computer must listen first to ensure that no other station is in the process of transmitting.

Which access method uses a "listen before sending" strategy? a. Token passing b. CSMA/CD c. Token bus d. Polling

c. Logical bus topology Note: Wireless LANs use a physical star topology because they connect through a central access point. However, only one device can transmit at a time and all devices hear the transmission, so a wireless LAN can be considered a logical bus topology.

Which best describes a typical wireless LAN? a. Logical ring topology b. Logical switching topology c. Logical bus topology d. Logical star topology

d. CSMA/CA

Which media access method does Wi-Fi use? a. CSMA/CD b. Token bus c. Demand priority d. CSMA/CA

b. Logical bus Note: The main logical topologies are bus, ring, and switched. A logical bus can be implemented as a physical star or a physical bus and is used with hub-based Ethernet and Wi-Fi networks.

Which of the following describes a hub-based Ethernet network? a. Physical bus b. Logical bus c. Physical switching d. Logical star

c. Physical topology Note: The arrangement of cabling and how cables connect one device to another in a network are considered the network's PHYSICAL topology, and the path data travels between computers on a network is considered the network's LOGICAL topology.

Which of the following describes the arrangement of network cabling between devices? a. Logical topology b. Networking technology c. Physical topology d. Media access method

b. Creates dynamic connections d. Uses a physical star topology Note: A switched logical topology using a physical star topology running Ethernet is by far the most common topology/technology combination now and likely will be well into the future. A switched topology creates dynamic connections or circuits between two devices whenever data is sent. This topology is sometimes considered a switched point-to-point topology because a circuit is established between two points as needed to transfer data (like turning on a switch), and then the circuit is broken when it's no longer needed (like turning off a switch).

Which of the following is a characteristic of a switched logical topology? (Choose all that apply.) a. Uses a physical bus topology b. Creates dynamic connections c. Sometimes called a shared-media topology d. Uses a physical star topology

a. Can be used in electrically noisy environments c. Carries data over longer distances than UTP does Note: Fiber-optic cabling uses extremely thin strands of glass to carry pulses of light long distances and at high data rates. Because of its capability to carry data over long distances (several hundred to several thousand meters), it's also used in WAN applications frequently. Fiber-optic cabling isn't susceptible to electrical interference, so unlike UTP, it can be used in electrically noisy environments. It requires two strands of fiber to make a network connection: one for transmitting and one for receiving.

Which of the following is a characteristic of fiber-optic cabling? (Choose all that apply.) a. Can be used in electrically noisy environments b. Requires only a single strand of fiber for network connections c. Carries data over longer distances than UTP does d. Lower bandwidth capability

c. Has a distance limitation of 100 meters d. Susceptible to electrical interference Note: Unshielded Twisted Pair (UTP) is the most common media type in LANs. It consists of four pairs of copper wire. Up to Category 8 as of this writing. The higher the category, the higher the cable's bandwidth potential. Category 5 Enhanced (Cat 5E) and Category 6 (Cat 6) are the most common in wired LANs, allowing speeds up to 10 Gbps. UTP cabling is used in physical star networks, and the maximum cable length from NIC to switch is 100 meters in LAN applications. UTP cabling is susceptible to electrical interference, which can cause data corruption, so it shouldn't be used in electrically noisy environments.

Which of the following is a characteristic of unshielded twisted-pair cabling? (Choose all that apply.) a. Consists of four wires b. Commonly used in physical bus topologies c. Has a distance limitation of 100 meters d. Susceptible to electrical interference

a. Often used as backbone cabling d. Uses two strands of fiber Note: 100BaseFX Ethernet In environments that aren't conducive to using copper wiring to carry network data (such as electrically noisy settings) or where the cable run length exceeds the reach of twisted-pair wiring, the only real choice in a wired network is fiber optics. 100BaseFX (with the F indicating "fiber optic"), which uses two strands of fiber-optic cable, is often the best choice of network technology in these settings.

Which of the following is a feature of 100BaseFX? (Choose all that apply.) a. Often used as backbone cabling b. Best when only short cable runs are needed c. The fastest of the Ethernet standards d. Uses two strands of fiber

b. FCS (frame check sequence) c. Destination MAC Address d. Data Note: A frame is the unit of network information NICs and switches work with. It's the NIC's responsibility to transmit and receive frames and a switch's responsibility to forward frames out the correct switch port to get the frame to its destination. Frames consist of: •A 14-byte frame header composed of these three fields: 1. A 6-byte Destination MAC Address field, 2. A 6-byte Source MAC Address field, 3. A 2-byte Type field •A Data field from 46 to 1500 bytes •A frame trailer (frame check sequence [FCS]) of 4 bytes

Which of the following is a field of the most common Ethernet frame type? (Choose all that apply.) a. ARP trailer b. FCS (frame check sequence) c. Destination MAC Address d. Data e. MAC type

a. Allows faster technologies than a bus does c. Centralized monitoring of network traffic Note: Some advantages of a physical star topology are the following: • Much faster technologies are used than in a bus topology. • Centralized monitoring and management of network traffic are possible. • Network upgrades are easier.

Which of the following is an advantage of a star topology? (Choose all that apply.) a. Allows faster technologies than a bus does b. Requires less cabling than a bus c. Centralized monitoring of network traffic d. No single point of failure

a. Scalable b. Best-effort delivery system Note: Ethernet Error Handling- One reason for Ethernet's low cost and scalability is its simplicity. It's considered a best-effort delivery system, meaning that when a frame is sent, there's no acknowledgement or verification that the frame arrived at its intended destination. Ethernet relies on network protocols, such as TCP/IP, to ensure reliable delivery of data. It's similar to the package delivery guy at a company. His job is to take what he's given to its intended destination; it's the package receiver's job to verify its contents and let the sender know it was received.

Which of the following is considered a property of Ethernet? (Choose all that apply.) a. Scalable b. Best-effort delivery system c. Guaranteed delivery system d. Obsolete technology

b. Collision domain

Which of the following is defined by the extent to which signals in an Ethernet bus topology network are propagated? a. Physical domain b. Collision domain c. Broadcast domain d. Logical domain

b. Collision detection is turned off. c. It's possible only with switches. Note: CSMA/CD isn't used because a collision can't occur in full-duplex mode. Because full-duplex mode eliminates the delays caused by CSMA/CD and allows double the network bandwidth, most Ethernet LANs now operate in this mode using switches.

Which of the following is true about full-duplex Ethernet? (Choose all that apply.) a. Stations can transmit and receive but not at the same time. b. Collision detection is turned off. c. It's possible only with switches. d. It allows a physical bus to operate much faster.

b. Uses a central device d. Most like a logical bus and physical star Note: Most Wi-Fi networks operate in infrastructure mode, meaning wireless stations connect through a wireless AP before they can begin communicating with other devices. Infrastructure mode uses a logical bus topology because all nodes hear all communications (in most cases). The physical topology with a central device that all nodes communicate with, it most resembles a star topology.

Which of the following is true about infrastructure mode in wireless networks? (Choose all that apply.) a. Best used for temporary networks b. Uses a central device c. Resembles a physical bus and logical ring d. Most like a logical bus and physical star

d. Operates only in full-duplex mode Note: 10GBaseT Ethernet The 2006 IEEE 802.3an standard defines 10 Gigabit Ethernet as running over four pairs of Category 6A or Category 7 UTP cabling. Unlike the other BaseT Ethernet standards, 10GBaseT operates only in full-duplex mode, so you won't find any 10 Gbps hubs—only switches.

Which of the following is true of IEEE 802.3an? a. Requires two pairs of wires b. Uses Category 5 or higher cabling c. Currently best for desktop computers d. Operates only in full-duplex mode

c. A destination address of 12 hexadecimal Fs is a broadcast. Every Ethernet station must have a physical or MAC address. A MAC address consists of 48 bits expressed as 12 hexadecimal digits. When a frame is sent to the network medium, it must contain both source and destination MAC addresses. When a network interface detects a frame on the media, the NIC reads the frame's destination address and compares it with its own MAC address. If they match or if the destination address is the broadcast MAC address (all binary 1s or FF:FF:FF:FF:FF:FF in hexadecimal), the NIC reads the frame and sends it to the network protocol for further processing.

Which of the following is true of a MAC address? a. All binary 1s in the source address indicates a broadcast frame. b. It's sometimes called a logical address. c. A destination address of 12 hexadecimal Fs is a broadcast. d. It's composed of 12 bits.

d. Wireless bridge Note: point-to-point topology- A topology in which cabling creates a direct link between two devices; used most often in WANs or in wireless networks to create a wireless bridge.

Which technology is likely to be implemented as a point-to-point physical topology? a. Wi-Fi infrastructure mode b. FDDI c. Ethernet d. Wireless bridge

b. PMP Note: Point-to-Multipoint Topology A point-to-multipoint (PMP) topology is an arrangement in which a central device communicates with two or more other devices, and all communication goes through the central device. It's often used in WANs where a main office has connections to several branch offices via a router.

Which topology is likely to be deployed in a WAN where there's a central office and three branch offices, and you want all traffic from the branch offices to go through the central office network? a. Ring b. PMP c. Mesh d. Point-to-point

c. Physical bus

Which topology most likely uses coaxial cabling? a. Physical star b. Logical ring c. Physical bus d. Logical switching

d. Scattering.

Which type of Wi-Fi signal interference is most likely to be caused by leaves on trees? a. Diffraction b. Reflection c. Refraction d. Scattering.

a. Unidirectional Note: Unidirectional antenna—With a unidirectional antenna, signals are focused in a single direction, which makes them ideal for placement at one end of long, narrow spaces or to cover distances between buildings. Omnidirectional antenna—the signals radiate out from the antenna with equal strength in all directions. Omnidirectional antennas are used most often in WLANs because they cover a broad area.

You're configuring a WLAN in a long narrow ballroom. The only place you can put the AP is at the far end of the room. Which type of antenna should you use? a. Unidirectional b. Bidirectional c. Omnidirectional d. Semidirectional