CCNA Basic Switching and Switch Configuration Questions
Chapter 12 True/False Indicate whether the statement is true or false.____ 1. Routers, switches, bridges, and gateways segment networks and thus create separate collision domains.____ 2. When a segment has too much broadcast traffic, utilization increases and network performance in general benefits.____ 3. IEEE 802.3u specifies two types of repeaters: Class I and Class II. Class II repeaters have higher latency than Class I repeaters.____ 4. The main difference between a switch and a bridge is that the switch typically connects multiple stations indi- vidually, thereby segmenting a LAN into multiple collision domains.____ 5. You cannot actually configure a router until you get to enable mode. Multiple Choice Identify the choice that best completes the statement or answers the question.____ 6. A(n) ____ is the physical area in which a packet collision might occur. a. backoff domain c. IPG domain b. collision domain d. jam domain____ 7. Stations on a network ____ packets to other stations to make their presence known on the network and to car- ry out normal network tasks such as IP address-to-MAC address resolution. a. broadcast c. multicast b. unicast d. anycast____ 8. ____ refers to the amount of time required to transmit one data bit on a network. a. Transmission time c. Latency b. Slot time d. Bit time____ 9. ____ specifies that all collisions should be detected from anywhere in a network in less time than is required to place a 64-byte frame on the network. a. Latency c. Slot time b. Transmission time d. Bit time____ 10. A ____ error indicates that bits of a frame were corrupted during transmission, a. frame check sequence (FCS) c. long frame b. jabber d. short frame____ 11. A(n) ____ occurs when two stations transmit more than 64 bytes of data frames before detecting a collision. a. jabber c. late collision b. NIC error d. alignment error____ 12. A bridge maintains a ____ that maps the MAC addresses on each segment to the corresponding port on the bridge to which each segment is connected. a. multicast table c. bandwidth table b. map table d. bridging table
____ 13. A ____ operates at layer 3 of the OSI reference model. It interprets the Network layer protocol and makes for- warding decisions based on the layer 3 address. a. switch c. bridge b. router d. hub____ 14. In ____ memory buffering, each port has a certain amount of memory that it can use to store frames. a. exclusive c. port-based b. shared d. content-addressable____ 15. With ____ memory buffering, any port can store frames in the shared memory buffer. a. content-addressable c. port-based b. shared d. exclusive____ 16. Some switches can interconnect network interfaces of different speeds. These switches use ____ switching and, typically, a shared memory buffer. a. symmetric c. virtual b. shared d. asymmetric____ 17. Switches that use ____ forwarding start sending a frame immediately after reading the destination MAC ad- dress into their buffers. a. cut-through c. fragment-free b. store-and-forward d. adaptive cut-through forwarding____ 18. ____ switches read the entire frame, no matter how large, into their buffers before forwarding. a. Fast-forward c. fragment-free b. Store-and-forward d. cut-through____ 19. ____ represents an effort to provide more error-reducing benefits than cut-through switching, while keeping latency lower than does store-and-forward switching. a. Fragment-free forwarding c. Adaptive cut-through forwarding b. Fast forwarding d. Adaptive fast forwarding____ 20. Fragment-free switches are also known as ____ switches. a. fast forwarding c. cut-through b. error sensing d. modified cut-through____ 21. Two types of operating systems are in use on Cisco switches: IOS-based and ____. a. terminal-based c. set-based b. command-based d. prompt-based____ 22. To enter enable mode, type ____ at the command-line prompt and then press Enter. a. enable c. enable on b. mode -enable d. set enable____ 23. To start configuration mode, first type ____ at the command prompt. a. cfg trmnl c. config t b. config tty d. cfg t____ 24. Generally speaking, a switch does not require an IP address, because switches operate mainly on Layer 2 (____ addresses). a. IP c. IPX b. TCP d. MAC
____ 25. To view the configuration of a port, use the ____ command. a. display c. interface b. show d. port____ 26. Cisco uses the term ____ to refer to the process by which a switch learns addresses on its own. a. ipg learn c. sticky learn b. switch learn d. sticky memory Completion Complete each statement. 27. ____________________ is a network access method (or media access method) originated by the University of Hawaii, later adopted by Xerox Corporation, and standardized as IEEE 802.3 in the early 1980s. 28. The amount of time it takes for a packet to be sent from one device to another is called the ____________________. 29. In ____________________ communications, devices can send and receive signals, but not at the same time. 30. In ____________________ communications, devices can send and receive signals simultaneously. 31. The MAC-to-switch-port mapping is stored in the switch’s ______________________________. Matching Match each item with a statement below: a. CSMA/CD f. Bridge b. Broadcast storm g. Symmetric switching c. Latency h. Adaptive cut-through forwarding d. 5-4-3 rule i. VLAN e. Alignment error____ 32. a frame with an FCS error and an octet missing____ 33. virtual local area network that allows you to logically segment a network____ 34. switches that require all attached network interface devices to use the same transmit/receive speed____ 35. a sudden rush of network transmissions that causes all other network communications to slow down due to the volume of data competing for access to the same bandwidth on the communications medium____ 36. segments a network by filtering traffic at the Data Link layer____ 37. the length of time that is required to forward, send, or otherwise propagate a data frame____ 38. also known as error sensing____ 39. limits collision domains to five segments of wire, four repeaters and/or hubs, and three populated hubs be- tween any two stations on a 10-Mbps network____ 40. Ethernet contention method
Short Answer41. How are collisions handled by CSMA/CD?42. Describe a simple way to reduce broadcast traffic.43. What are some of the frame size errors that occur on Ethernet networks?44. What are the three defined implementations of Fast Ethernet?45. What are the Gigabit Ethernet specifications and the governing IEEE standards?46. What are the benefits of using full-duplex?47. What are the benefits provided by switches?48. Describe cut-through forwarding switching.49. How can you set the host name on a Cisco Catalyst switch?
50. Describe the violation command for configuring port security. Chapter 12 Answer Section TRUE/FALSE 1. ANS: T PTS: 1 REF: 338 2. ANS: F PTS: 1 REF: 339 3. ANS: F PTS: 1 REF: 342 4. ANS: T PTS: 1 REF: 346 5. ANS: T PTS: 1 REF: 351 MULTIPLE CHOICE 6. ANS: B PTS: 1 REF: 338 7. ANS: A PTS: 1 REF: 339 8. ANS: D PTS: 1 REF: 340 9. ANS: C PTS: 1 REF: 34010. ANS: A PTS: 1 REF: 34111. ANS: C PTS: 1 REF: 34112. ANS: D PTS: 1 REF: 34513. ANS: B PTS: 1 REF: 34514. ANS: C PTS: 1 REF: 34815. ANS: B PTS: 1 REF: 34816. ANS: D PTS: 1 REF: 34817. ANS: A PTS: 1 REF: 34918. ANS: B PTS: 1 REF: 35019. ANS: A PTS: 1 REF: 35020. ANS: D PTS: 1 REF: 35121. ANS: C PTS: 1 REF: 35122. ANS: A PTS: 1 REF: 35123. ANS: C PTS: 1 REF: 35124. ANS: D PTS: 1 REF: 35225. ANS: B PTS: 1 REF: 35326. ANS: C PTS: 1 REF: 354 COMPLETION27. ANS: Ethernet PTS: 1 REF: 33828. ANS: transmission time PTS: 1 REF: 34029. ANS: half-duplex
PTS: 1 REF: 34330. ANS: full-duplex duplex PTS: 1 REF: 34331. ANS: content-addressable memory (CAM) content-addressable memory CAM PTS: 1 REF: 348 MATCHING32. ANS: E PTS: 1 REF: 34133. ANS: I PTS: 1 REF: 35234. ANS: G PTS: 1 REF: 34835. ANS: B PTS: 1 REF: 33936. ANS: F PTS: 1 REF: 34437. ANS: C PTS: 1 REF: 34038. ANS: H PTS: 1 REF: 35139. ANS: D PTS: 1 REF: 34040. ANS: A PTS: 1 REF: 338 SHORT ANSWER41. ANS: Even though stations must listen to the wire before sending a transmission, two stations could listen to the wire simultaneously and not sense a carrier signal. In such a case, both stations might begin to transmit their data simultaneously. Shortly after the simultaneous transmissions, a collision would occur on the network wire. The stations would detect the collision as their transmitted signals collided with one another. Once a collision is detected, the first station to detect the collision transmits a 32-bit jam signal that tells all other stations not to transmit for a brief period (9.6 microseconds or slightly more). The jam signal is used to ensure that all stations are aware that a collision has occurred. After the jam signal is transmitted, the two sta- tions that caused the collision use an algorithm to enter a backoff period, which causes them not to transmit for a random interval. The backoff period is an attempt to ensure that the two stations do not immediately cause another collision. PTS: 1 REF: 33842. ANS:
One simple way to reduce broadcast traffic is to reduce the number of services that servers provide on your network and to limit the number of protocols in use on your network. Limiting the number of services will help because each computer that provides a service, such as file sharing, broadcasts its service at a periodic interval over each protocol it has configured. Many operating systems allow you to bind the service selective- ly to only a specific protocol, which will reduce broadcast traffic on the network. You can also eliminate un- necessary protocols to eliminate broadcast traffic on the network. An example of an unnecessary protocol is the IPX protocol on a server in an IP-only network. In this case, services would be advertised on both IP and IPX, when other stations would only be communicating via IP. IPX advertisements and the use of the IPX protocol is unnecessary in this case because no other stations on the network would be using IPX. PTS: 1 REF: 33943. ANS: An Ethernet packet sent between two stations should be between 64 bytes and 1518 bytes. According to Eth- ernet specifications, shorter or longer frames are errors. Frame size errors that occur on Ethernet networks in- clude: • Short frame or runt—A frame that is shorter than 64 bytes. A collision, a faulty network adapter, corrupt NIC software drivers, or a repeater fault can cause this error. • Long frame or giant—A frame that is larger than 1518 bytes. Because 1518 is the largest legal frame size, a long frame is too large to be valid. A collision, faulty network adapter, illegal hardware configuration, transceiver or cable fault, termination problem, corrupt NIC software drivers, repeater fault, or noise can cause this error. • Jabber—This is another classification for giant or long frames. This frame is longer than Ethernet standards allow (1518 bytes) and has an incorrect frame check sequence (FCS). PTS: 1 REF: 34144. ANS: Fast Ethernet, which is defined under the IEEE 802.3u standard, has three defined implementations: • 100Base-TX—Uses two pairs of either Category 5 unshielded twisted-pair (UTP) or shielded twisted-pair (STP); one pair is used for transmit (TX), and the other is used for receive (RX). The maximum segment length is 100 meters; two Class II repeaters and a five-meter patch cable can be used to create a maximum distance of 205 meters between stations for each collision domain. • 100Base-T4—Uses four pairs of either Category 3, 4, or 5 UTP cable; one pair is used for TX, one pair for RX, and two pairs are used as bidirectional data pairs. The maximum segment length is 100 meters; as with 100Base-TX, two Class II repeaters and a five-meter patch cable can be used to create a maximum distance of 205 meters between stations for each collision domain. Because all four pairs are used, the T4 specification does not support full-duplexing, which is discussed in the next section. • 100Base-FX—Uses multimode fiber-optic (MMF) cable with one TX and one RX strand per link. The max- imum segment length is 412 meters. PTS: 1 REF: 34245. ANS: The Gigabit Ethernet specifications and the governing IEEE standards are: • 1000Base-TX (802.3ab)—Uses four pairs of Category 5 unshielded twisted-pair cable. The maximum seg- ment length is 100 meters. • 1000Base-SX (802.3z)—Uses multimode fiber. The maximum segment length varies based on what type of fiber is being used. For example, using a 62.5 micron core, the maximum length is 220 meters. When using a 50 micron core, the maximum length is 550 meters. • 1000Base-LX (802.3z)—Uses single-mode fiber. The maximum distance for this standard is 10 kilometers. • 1000Base-CX (802.3z)—Uses shielded twisted-pair copper cabling. The maximum segment length is 25 me- ters.
PTS: 1 REF: 34346. ANS: The benefits of using full-duplex are: • Time is not wasted retransmitting frames because collisions do not occur. • The full bandwidth is available in both directions because the send and receive functions are separate. • Stations do not have to wait until other stations complete their transmissions because only one transmitter is used for each twisted pair. PTS: 1 REF: 34447. ANS: Switches provide the following benefits: • Reduction in network traffic and collisions • Increase in available bandwidth per station, because stations can communicate in parallel • Increase in the effective distance of a LAN by dividing it into multiple collision domains • Increased security, because unicast traffic is sent directly to its destination and not to all other stations on the collision domain PTS: 1 REF: 34748. ANS: Switches that use cut-through forwarding start sending a frame immediately after reading the destination MAC address into their buffers. The main benefit of cut-through forwarding is a reduction in latency, because the forwarding decision is made almost immediately after the frame is received. For example, the switching decision is made after receiving 14 bytes of a standard Ethernet frame. The drawback to forwarding the frame immediately is the potential for errors in the frame that the switch would be unable to detect because the switch only reads a small portion of the frame into its buffer. Of course, any errors that occur in the preamble, start frame delimiter (SFD), or destination address fields will not be propagated by the switch, unless they are corrupted in such a way as to appear valid, which is highly unlikely. PTS: 1 REF: 349-35049. ANS: The actual task of setting the host name on the Cisco Catalyst switch is identical to setting the host name on a Cisco router. As with the router, the host name is only locally significant—that is, the function of the name is to identify the switch, not to provide any sort of Internet name resolution. It is best to select a name that clear- ly identifies the location of the switch. For example, if you worked for a company named HudLogic, Inc. and its switch was on the fourth floor of Room 410, you might name the switch Rm410HL. To configure this name, you would type: Switch(config)#hostname Rm410HL Once the host name is set, the prompt will change to reflect the name of the switch. Continuing our example, the prompt would change to: Rm410HL(config)# PTS: 1 REF: 35250. ANS:
The violation command dictates what happens when a switch encounters a violation of the configuredswitchport security. The default is to shut down the interface. You can also define the action with one of thefollowing three options: protect, restrict, and shutdown. The protect option stops forwarding oftraffic from any host that connects after the maximum number of MAC addresses has been learned. In our ex-ample, the maximum number of MAC addresses is 10. If the protect option was selected, the 11th addressand any subsequent new MAC addresses on the port would be prevented from communicating. The restrictoption also stops all traffic above the number of defined MAC addresses. In addition, it sends an alert that asecurity violation has occurred. The final option, shutdown, shuts the port down if a security violation oc-curs.PTS: 1 REF: 354