CCNA questions - section 2.txt

Card Set Information

Author:
Anonymous
ID:
199630
Filename:
CCNA questions - section 2.txt
Updated:
2013-02-11 02:32:49
Tags:
CCNA CCENT ICND1
Folders:

Description:
Open Ended Questions from Section 2 of Cisco CCNA/CCENT ICND1
Show Answers:

Home > Flashcards > Print Preview

The flashcards below were created by user Anonymous on FreezingBlue Flashcards. What would you like to do?


  1. What are the two names for the same CLI mode in a router or switch that, when accessed, enables you to issue EXEC commands that could be disruptive to router operations?
    Enable mode and privileged mode. Both names are commonly used and are found in Cisco documentation
  2. What are three methods of logging on to a router or switch?
    Console, auxiliaire port, and Telnet. All three cause the user to enter user EXEC mode
  3. What is the name of the user interface mode of operation in which you cannot issue disruptive commands?
    User EXEC mode
  4. What command do you use to receive command help if you know that a show command option begins with a c but you cannot recall the option?
    • show c?
    • Help would appear immediately after you typed the ? symbol. You would not need to press Enter after the ?. If you did so, the router or switch would try to execute the command with only the parameters that you had typed after the ?
  5. While you are logged in to a router or switch, you issue the command copy ? and get a response of “Unknown command, computer name, or host.” Offer an explanation for why this error message appears.
    You were in user mode. You must be in enable/privileged mode to use the "copy" command. When in user mode, the router does not provide help for privileged commands, and it treats the request for help as if there is no such command
  6. Is the number of retrievable commands based on the number of characters in each command, or is it simply a number of commands, regardless of their size?
    The number of commands. The length (that is, the number of characters) of each command does not affect the command history buffer
  7. How can you retrieve a previously used command? (Name two ways.)
    • Ctrl-p
    • up-arrow
  8. After typing show ip route, which is the only command that you typed since logging in to the router, you now want to issue the show ip arp command. What steps would you take to execute this command by using command-recall keystrokes?
    Press the up-arrow, press backspace 5 times, and type "arp". The up-arrow key retrieves the "show ip route" command. Backspace moves the cursor backward and erases the character. Typing inserts the characters into the line.
  9. What configuration command causes the router or switch to require a password from a user at the console? What configuration mode context must you be in? (That is, what command[s] must be typed before this command after entering configuration mode?) List the commands in the order in which they must be typed while in config mode.
    The "line console 0" command is a context-setting command; it adds no information to the configuration. The command can be typed from any part of configuration mode. The "login" command, which follows the "line console 0" command, tells Cisco IOS that a password prompt is desired at the console
  10. What configuration command is used to tell the router or switch the password that is required at the console? What configuration mode context must you be in? (That is, what command[s] must you type before this command after entering configuration mode?) List the commands in the order in which they must be typed while in config mode.
    The "password" command tells Cisco IOS the value that should be typed when a user wants access from the console. This value is requested by Cisco IOS because of the "login" command. The "password xxxxx" command must be typed while in console configuration mode, which is reached by typing "line console 0"
  11. What are the primary purposes of Flash memory in a Cisco router?
    To store Cisco IOS and microcode files. If microcode is upgraded, the files also reside in Flash memory
  12. What is the intended purpose of NVRAM memory in a Cisco router or switch?
    To store a single configuration file, used at router or switch load time. NVRAM does not support multiple files
  13. What does the NV stand for in NVRAM?
    Nonvolatile. NVRAM is battery powered if it is really RAM. In some routers or switches, Cisco has used a small portion of Flash memory for the purpose of NVRAM
  14. What is the intended purpose of RAM in a Cisco router or switch?
    RAM is used as Cisco IOS working memory (storing such things as routing tables or packets) and for Cisco IOS code storage. It also holds the currently-in-use configuration file called running-config
  15. What is the main purpose of ROM in a Cisco router?
    To store a small, limited-function version of IOS and to store bootstrap code. Typically, this type of IOS is used only during maintenance or emergencies
  16. What command sets the password that would be required after typing the enable command? Is that password encrypted by default?
    "enable password" or "enable secret". The password in the "enable" command is not encrypted, by default. The "enable secret" password is encoded using MD5
  17. To have the correct syntax, what must you add to the following configuration command? banner This is Ivan Denisovich’s Gorno Router--Do Not Use
    As typed, IOS would think that the letter T is the delimiter character, so the banner actually would be "his is Ivan…". The motd parameter is not shown because it is not required. An alternate correct command would be this: banner motd # This is Ivan… Do Not Use #
  18. Name two commands that affect the text used as the command prompt.
    "hostname" & "prompt"
  19. When using setup mode, you are prompted at the end of the process for whether you want to use the configuration parameters that you just typed in. Which type of memory is this configuration stored in if you type yes?
    Both NVRAM and RAM. Setup is the only Cisco IOS feature that modifies both the active and the startup configuration files as the result of one action by the user
  20. Is the password required at the console the same one that is required when Telnet is used to access a router or switch?
    No. The Telnet (virtual terminal) password is not the same password, although many installations use the same value
  21. Name two commands used to view the configuration to be used at the next reload of the router or switch. Which one is a more recent addition to Cisco IOS Software?
    "show config" and "show startup-config". The latter is the newer and, hopefully, is easier to remember
  22. Name two commands used to view the configuration that currently is used in a router or switch. Which one is a more recent addition to Cisco IOS Software?
    "write terminal" and "show running-config". The latter is newer command and, hopefully, is easier to remember.
  23. True or false: The copy startup-config running-config command always changes the currently used configuration for this router or switch to exactly match what is in the startup configuration file. Explain.
    False. Some configuration commands do not replace an existing command but simply are added to a list of related commands. If such a list exists, the "copy startup-config running-config" command simply adds those commands to the end of the list. Many of these lists in a router or switch configuration are order dependent
  24. What are the two names for the switch’s mode of operation that, when accessed, enables you to issue commands that could be disruptive to switch operations?
    Enable mode and privileged mode. Both names are commonly used and found in Cisco documentation
  25. What configuration command causes the switch to require a password from a user at the console? What configuration mode context must you be in? (That is, what command[s] must be typed before this command after entering configuration mode?) List the commands in the order in which they must be typed while in config mode.
    • line console 0
    • login
    • The "line console 0" command is a context-setting command; it adds no information to the configuration. The command can be typed from any part of configuration mode. The "login" command, which follows the "line console 0" command, tells IOS that a password prompt is desired at the console
  26. What configuration command is used to tell the switch the password that is required at the console? What configuration mode context must you be in? (That is, what command[s] must you type before this command after entering configuration mode?) List the commands in the order in which they must be typed while in config mode.
    • line console 0
    • password xxxxx
    • The "password" command tells IOS the value that should be typed when a user wants access from the console. This value is requested by IOS because of the "login" command. The "password xxxxx" must be typed while in console configuration mode, which is reached by typing "line console 0"
  27. Name three methods of internal switching on typical switches today. Which provides less latency for an individual frame?
    • Store-and-forward
    • Cut-through
    • Fragment-free switching
  28. Describe how a transparent bridge decides whether it should forward a frame, and tell how it chooses the output interface.
    The bridge examines the destination MAC address of a frame and looks for the address in its bridge (or address) table. If found, the matching entry tells the bridge which output interface to use to forward the frame. If not found, the bridge forwards the frame out all other interfaces except for interfaces blocked by STP and the interface in which the frame was received. The bridge table is build by examining incoming frames' source MAC address
  29. Define the term collision domain.
    A collision domain is a set of Ethernet devices for which concurrent transmission of a frame by any two of them will result in a collision. Bridges, switches, and routers separate LAN segments into different collision domains. Repeaters and shared hubs do not separate segments into different collision domains.
  30. Name two benefits of LAN segmentation using transparent bridges.
    • The main benefits are reduced collisions and more cumulative bandwidth.
    • Multiple 10- or 100-Mbps Ethernet segments are created, and unicasts between devices on the same segment are not forwarded by the bridge, which reduces overhead. Because frames can be sent over each segment at the same time, it increases the overall bandwidth available in the network.
  31. What routing protocol does a transparent bridge use to learn about Layer 3 addressing groupings?
    None. Bridges do not use routing protocols. Transparent bridges do not care about Layer 3 address groupings. Devices on either side of a transparent bridge are in the same Layer 3 group—in other words, the same IP subnet or IPX network.
  32. If a Fast Ethernet NIC currently is receiving a frame, can it begin sending a frame?
    Yes, if the NIC is operating in full-duplex mode.
  33. Why did Ethernet networks’ performance improve with the advent of bridges?
    Before bridges and switches existed, all devices were cabled to the same shared Ethernet. The CSMA/CD algorithm was used to determine who got to send across the Ethernet. As the amount of traffic increased, collisions and waiting (because of CSMA/CD) increased, so frames took longer to send. Bridges separated the network into multiple collision domains, reducing collisions and allowing devices on opposite sides of the bridge to send concurrently.
  34. Why did Ethernet networks’ performance improve with the advent of switches?
    Before bridges and switches existed, all devices were cabled to the same shared Ethernet. The CSMA/CD algorithm was used to determine who got to send across the Ethernet. As the amount of traffic increased, collisions and waiting (because of CSMA/CD) increased, so frames took longer to send. Switches separated the network into multiple collision domains, typically one per port, reducing collisions and allowing devices on opposite sides of the bridge to send concurrently.
  35. What are two key differences between a 10-Mbps NIC and a 10/100-Mbps NIC?
    The obvious benefit is that the 10/100-Mbps NIC can run at 100 Mbps. The other benefit is that 10/100-Mbps NICs can autonegotiate both speed and duplex between themselves and the device that they are cabled to, typically a LAN switch.
  36. Assume that a building has 100 devices attached to the same Ethernet. These users then are migrated onto two separate shared Ethernet segments, each with 50 devices, with a transparent bridge between them. List two benefits that would be derived for a typical user.
    Fewer collisions should occur due to having two collision domains. Also, less waiting should occur because twice as much capacity exists.
  37. Assume that a building has 100 devices attached to the same Ethernet. These devices are migrated to two different shared Ethernet segments, each with 50 devices. The two segments are connected to a Cisco LAN switch to allow communication between the two sets of users. List two benefits that would be derived for a typical user.
    Two switch ports are used, which reduces the possibility of collisions. Also, each segment has its own 10- or 100-Mbps capacity, allowing more throughput and reducing the likelihood of collisions. Furthermore, some Cisco switches can reduce the flow of multicasts by using the Cisco Group Message Protocol (CGMP) and IGMP snooping.
  38. How fast is Fast Ethernet?
    100 million bits per second (100 Mbps).
  39. How does a transparent bridge build its address table?
    The bridge listens for incoming frames and examines the source MAC address. If it is not in the table, the source address is added, along with the port (interface) by which the frame entered the bridge. The bridge also marks an entry for freshness so that entries can be removed after a period of disuse. This reduces table size and allows for easier table changes in case a spanning-tree change forces more significant changes in the bridge (address) table.
  40. How many bytes long is a MAC address?
    6 bytes long, or 48 bits.
  41. Does a bridge or switch examine just the incoming frame’s source MAC, just the destination MAC, or both? Why does it examine the one(s) that it examines?
    The bridge or switch examines both MAC addresses. The source is examined so that entries can be added to the bridge/address table. The destination address is examined to determine the interface out which to forward the frame. Table lookup is required for both addresses for any frame that enters an interface. That is one of the reasons that LAN switches, which have a much larger number of interfaces than do traditional bridges, need to have optimized hardware and logic to perform table lookup quickly.
  42. Define the term broadcast domain.
    A broadcast domain is a set of Ethernet devices for which a broadcast sent by any one of them should be received by all others in the group. Unlike routers, bridges and switches do not stop the flow of broadcasts. Two segments separated by a router each would be in different broadcast domains. A switch can create multiple broadcast domains by creating multiple VLANs, but a router must be used to route packets between the VLANs.
  43. Describe the benefits of creating three VLANs of 25 ports each, versus a single VLAN of 75 ports, in each case using a single switch. Assume that all ports are switched ports (each port is a different collision domain).
    Three different broadcast domains are created with three VLANs, so the devices’ CPU utilization should decrease because of decreased broadcast traffic. Traffic between devices in different VLANs will pass through some routing function, which can add some latency for those packets. Better management and control are gained by including a router in the path for those packets.
  44. Explain the function of the loopback and collision-detection features of an Ethernet NIC in relation to half-duplex and full-duplex operations.
    The loopback feature copies the transmitted frame back onto the receive pins on the NIC interface. The collision-detection logic compares the received frame to the transmitted frame during transmission; if the signals do not match, a collision is occurring. With full-duplex operation, collisions cannot occur, so the loopback and collision-detection features are purposefully disabled, and concurrent transmission and reception is allowed.
  45. Describe the benefit of the Spanning Tree Protocol as used by transparent bridges and switches.
    Physically redundant paths in the network are allowed to exist and be used when other paths fail. Also, loops in the bridged network are avoided. Loops are particularly bad because bridging uses LAN headers, which do not provide a mechanism to mark a frame so that its lifetime can be limited; in other words, the frame can loop forever.
  46. Define the term VLAN.
    Virtual LAN (VLAN) refers to the process of treating one subset of a switch’s interfaces as one broadcast domain. Broadcasts from one VLAN are not forwarded to other VLANs; unicasts between VLANs must use a router. Advanced methods, such as Layer 3 switching, can be used to allow the LAN switch to forward traffic between VLANs without each individual frame being routed by a router.
  47. Must all members of the same VLAN be in the same collision domain, the same broadcast domain, or both?
    By definition, members of the same VLAN are all part of the same broadcast domain. They might all be in the same collision domain, but only if all devices in the VLAN are connected to hubs.
  48. Describe why a 10BASE-T network using a hub is considered to be a logical bus topology.
    A physical bus causes the transmitted electrical signal to be propagated to all devices connected to the bus. A 10BASE-T hub repeats a signal entering one port out all the other ports, ensuring that all devices receive the same signal. Hubs do not have any logic to prevent some frames from being sent out ports (all signals are repeated), creating a single collision domain, just like a physical bus.
  49. Compare and contrast full-mesh versus partial-mesh topologies, in relation to physical topologies.
    In a full mesh, for a particular set of networking devices, a direct cable connects each pair of devices. For a partial mesh, some pairs of devices are not directly connected.
  50. Compare and contrast full-mesh versus partial-mesh topologies, in relation to logical topologies.
    Regardless of the physical topology, a topology is considered a logical full mesh if each pair of devices can communicate directly, and is considered a partial mesh if some pairs cannot communicate directly. A Frame Relay network uses a star physical topology. Depending on what VCs have been defined, it might use a logical full mesh or a logical partial mesh.
  51. Which wires are used by a typical Ethernet CAT 5 cable for 100BASE-TX? Which ones are used for transmit, and which ones are used to receive, by an Ethernet card?
    Ethernet cards transmit on the pair using pins 1 and 2, and receive on the pair at pins 3 and 6.
  52. Which TIA standards for UTP cabling support 10BASE-T?
    CAT 3, 5, 5e, and 6.
  53. What are key differences between multimode and single-mode optical cabling?
    • Multimode cabling typically supports shorter distances than single-mode.
    • Single-mode uses a much smaller diameter for the glass fiber and supports greater distances.
  54. What types of cabling are least susceptible to having someone eavesdrop and somehow discover what is being transmitted over the cable?
    Optical cables do not emit any EM radiation outside the cable. So, you cannot simply sense what signal is crossing over an optical cable without physically breaking into the cable, which makes the cable unusable.
  55. What are the IEEE standards for 10BASE-T, Fast Ethernet, Gigabit Ethernet, and 10-Gigabit Ethernet?
    802.3 (10BASE-T), 802.3u (Fast Ethernet), 802.3z and 802.3ab (Gigabit Ethernet), and 802.3ae (10-Gigabit Ethernet).
  56. Which variations on the Fast Ethernet and Gigabit standard use IEEE 802.3 MAC and 802.2 LLC framing?
    All of them.
  57. What are some of the differences between 10-Gigabit Ethernet and other types of Ethernet?
    The speed, of course, is the obvious difference. Additionally, 10-Gigabit Ethernet is allowed to be used in a point-to-point topology only, and it supports full duplex only.
  58. What IEEE standards are used by an 802.11 access point?
    The access point uses 802.11 standards for communication across the wireless LAN, including 802.2 LLC. It also connects to a wired LAN, so it uses 802.3 for its wired Ethernet.
  59. What does the term line-of-sight mean in relation to wireless communications?
    Line-of-sight means that you can stand beside one device and see the other device. Some wireless technologies require a line-of-sight, and others do not.
  60. List five key pieces of information that can be gathered using CDP.
    Device identifier, address list, port identifier, capabilities list, and platform.
  61. Imagine a network with Switch1, connected to Router1, with a point-to-point serial link to Router2, which, in turn, is connected to Switch2. Assuming that you are logged in to R1, what commands could be used to find the IP addresses of Router2 and Switch1 without logging in to either device?
    On Router1, you could use either the show cdp neighbor detail command or the show cdp entry command. Both commands list IP addresses of the neighboring devices, assuming that CDP is up and working.
  62. Imagine that a network with Switch1 is connected to Router1, with a point-to-point serial link to Router2, which, in turn, is connected to Switch2. You can log in only to Switch1. Which of the other devices could Switch1 learn about using CDP? Why?
    Switch1 could learn about only Router1 because CDP learns information about only devices that are connected to the same data link.
  63. What command lists a brief one-line description of CDP information about each neighbor?
    The show cdp neighbor command.

What would you like to do?

Home > Flashcards > Print Preview