Networking I-Chapter 3

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. Allows faster technologies than a bus does. c. Centralized monitoring of network traffic. A Physical star toplogy netowkr uses a central device, such as a hub or switch to interconnect computers in a LAN. Each computer has a single length of cable going from its NIC to the central device. Advantages: * Much faster technology are used than in a bus toplogy * Centralized Monitoring and management of network traffice are possible * Network upgrades are easier. Pages 96-97

Which of the following is a feature of 100BasedFX? (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

a. Often used as backbone cabling d. Uses two strands of fiber

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

a. Scalable b. Best-effort

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

a. Unidirectional 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. page 125

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

b. CSMA/CD Carrier Sense Multiple Access with Collision Detection (CSMA/C) is a media access method in which a device must first listen (carrier sense) to the medium to be sure no other device is transmitting. If two devices transmit at the same time (multiple access), a colision occurs and is detected (collision detection). In this case all devices involved in the collision wait for a random period of time before transmitting again.

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 Domain The extent to which signals in an Ethernet bus topology network are propagated. page 109

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. Collision detection is turned off c. It's possible only with switches Full-Duplex mode by definition means a NIC can transmit and receive simultaneously. Therefore, when an Ethernet NIC is operating in full-duplex mode connected to a switch, CSMA/CD isn't used because a collisions 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 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

a can be used in electrically noisy enviroments c Carries data over longer distances that UTP. Fiber-Optic Cabling uses extremely thin strands of glass to carry pulses of light long distances and at high data rates. It's usually used in large internetworks to connect switches and routers and sometimes to connect high-speed servers to the network. Because of its capabilities 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. Requires two strands of fiber to make a network connection one for transmitting and one for receiving. Page 106

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

a. 802.11ac

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

b. Creates dynamic connects d. Uses a physical star topology. A switched logical topology using a physical star toplogy running Ethernet is by far the most common topology/technology combination now and likely will be well into the futher. A switch topology creates dynamic connections or circuits between two devices whenever data is sent. This topology is sometimes considered a switch 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 brown when it's no longer needed .

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

b. FCS c. Destination MAC Address d. Data Each Eithernet network frame is composed of the following * A 14-Byte frame header composed of a Destination MAC Address field, Source MAC Address field, type field * A Data field from 46 to 1500 bytes * A frame trailer (frame check sequence (FCS) of 4 bytes.

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

b. Logical bus A logical bus topology can be implemented as a physical bus (although this topology is now obsolete). When a logical bus is implemented as a physical stare using wired Ethernet, the center of the star is an Ethernet hub. Whatever the physical topology is, data transmitted from computer is received by all other computers. page 102

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.

b. Uses a central device d. Most like a logical bus and physical star

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

c. A destination address of 12 hexadecimal hexadecimal Fs in a broadcast. MAC address is an physical address that iconsists of 48 bits express as 12 hexadecimal digits. When a frame is sent to the network medium, it must contain both source and destination MAC address. When a network interface detects a fram 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:fFF:FF:FF:FF:FF in hexadecimal)

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

c. Has a distance limitation of 100 Meters d. Susceptible to electrical interference Unshielded twisted pair (UTP) is the most common media type of LANs. It consists of four pairs of copper wire, with each pair tightly twisted together and contained in a plastic sheath or jacket. The higher the category, the higher the cable's bandwidth potential. The most common in wired LANs allowing speeds up to 10Gbps. UTP cabling is used in physical star networks, and the maximum cable length from NIC to switch is 100 meters to the LAN application. UTP cabling is susceptible to electrical interference. Page 106

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

c. Logical bus topology 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. page 102

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

d. CSMA/CA Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)-an access control method used by @i-Fi networks, in which an acknowledgement is required for every packet sent, thereby avoiding most possiblities of a collision (collision avoidance) Page 132

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 office to go through the central office network. a. Ring b. PMP c. Mesh d. Point-to-point

d. PMP (Point-to-Multipoint topology) Point-to-Multipoint toplogy is an arrangement in which a central device communicates with two or more other devices, and all communications goes through the central device. It's often used in WANs where a main office has connections to several branch offices via a router. page 100

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

d. Scattering Scattering is caused by small, irregular objects, such as leaves, chain-link fences, dust, water droplets, and so forth. The signal changes direction in unpredictable ways, causing a loss in signal strength. Page 127

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

d. Wireless bridge Point-topoint toplogies are also used with wireless networks in what's called a Wireless bridge. Page 100

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

c. 11

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

c. Physical bus Technologies using this topology are limited to 10Mbps half-duplex communication because they used coaxial cabling. page 95

Which Wi-Fi standard uses beam forming to allow an AP to send data to multiple devices simultaneously? a. 802.11ac b. 802.11n c. 802.11a d. 802.11g

802.11ac

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

c. Physical topology Physical topology is the arrangement of cabling and how cables connect one device to another in a network. The most common physical topology is a star, but bus, ring, point-to-point, and mesh typologies are also used. Page 134 (definitions)

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

d. Operates only in full-duplex mode.