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CCNA 640-801 Test Questions

Answers/Explanations to CCNA Test 22
1. Which of the following statements would be the most accurate in regards to the Cisco three-layer hierarchical model?
It is important to consider high speed and low latency when designing the core layer.
When designing the distribution layer it is important to keep high reliability and speed in mind as well as choosing fast routing protocols with low convergence times.
The core layer is responsible for technologies such as Ethernet switching, as well as static routing.
The distribution layer handles traffic for remote services and creates separate collision domains.
Answer/Explanation
  • It is important to consider high speed and low latency when designing the core layer.

    The core layer is required to provide high reliability, and fast access speed, with routing protocols that have low convergence times.
    The access layer handles traffic for remote services and creates separate collision domains.
    The access layer is responsible for technologies such as Ethernet switching, as well as static routing.


    2. ICMP (Internet Control Message Protocol) is defined in RFC 792, and is used to manage and control the operation of a TCP/IP network. Which of the following would be the most accurate description of the error code: Protocol unreachable?
    This code is used to identify that the packet was delivered but the Transport layer protocol was not available at the host.
    The ‘Protocol unreachable’ code indicates that the packet was able to be delivered but the destination port was not able to be opened by an application.
    The ‘Protocol unreachable’ code indicates that the packet does not have a match in destination rout-ing table.
    This code is used to identify that the packet was able to be routed to a router that is connected at the destination, but the host is not responding.
    None of the above.
    Answer/Explanation
  • The ‘Protocol unreachable’ code indicates that the packet was able to be delivered but the destination port was not able to be opened by an application.

    The ‘Port unreachable’ code indicates that the packet was able to be delivered to the destination host, but a destination port could not be opened by an application. A ‘Network unreachable’ code indicates that there is not a match in the routing table for the destination of the packet.


    3. During the setup of a router which of the following statements would be the most accurate about aborting the router configuration process?
    Using the ‘Esc’ key and the ‘Alt’ key simultaneously will abort the installation process.
    Using the ‘Alt’ key and the ‘Q’ key simultaneously will abort the installation process.
    Using the ‘Ctrl’ key and the ‘C’ key simultaneously will abort the installation process.
    Using the ‘Alt’ key and the ‘Ctrl’ key simultaneously will abort the installation process.
    Answer/Explanation
  • Using the ‘Ctrl’ and the ‘C’ key simultaneously will abort the installation process.

    If there is not a configuration in NVRAM the router will enter setup mode automatically.
    Also while you are in setup mode all default settings are indicated in [square brackets] [ ].


    4. Which of the following commands would be used to encrypt a password with the MD-5 one-way hashing algorithm when configuring a router with IOS version 10.3?
    router#service password-encryption
    router(config)#service password-encryption
    router(config)#service password encryption
    router(config)#service-password encryption
    router#service password encryption
    router(config)#service passwordencryption
    Answer/Explanation
  • router(config)#service password-encryption

    Remember that after using the service password-encryption command from global configuration mode, the show running-configuration command must be ran from privileged mode and the command must be turned off from global configuration mode.


    5. Which of the following would be characteristics of PPP? (point to point protocol) (Choose all that apply).
    PPP will support multiple layer 3 protocols.
    PPP will support multiple layer 2 protocols.
    There is only one type of authentication available.
    PPP offers multiple types of authentication.
    There is only one correct answer.
    Answer/Explanation
  • PPP will support multiple layer 3 protocols.
  • PPP offers multiple types of authentication.

    PPP is actually a family of protocols, or may be referred to as a protocol suite, that has four main compoents.
    EIA/TIA 232 which is the standard for serial communication.
    HDLC for encapsulation over serial links.
    LCP (Link control protocol), establishes, configures, and terminates the connection,
    NCP (Network control program), allows for the configuration of different layer 3 protocols to be used.
    PPP supports multiple layer 3 protocols not layer 2 protocols.
    PPP offers 2 types of authentication. PAP (password authentication protocol) which is clear text, or CHAP (Challenge handshake authentication protocol) which encrupts the authentication process with the MD-5, 1 way hashing algorithm.


    6. Which of the following would describe the most significant difference between the 'enable' and the 'enable secret' password commands?'
    By default the enable secret command doesn't encrypt.
    By default the enable password command doesn't encrypt the password.
    The enable secret is not a valid Cisco IOS command.
    The enable password command is not a valid Cisco IOS command.
    None of these responses are correct.
    Answer/Explanation
  • By default the 'enable password' command doesn't encrypt the password.

    The enable password command does not encrypt by default. All passwords may be encrypted after they are entered using the service-encryption command.
    The enable secret is the command that is used to encrypt passwords by default with the MD5 hashing algorithm.
    The enable password was used on pre 10.3 versions of the Cisco IOS. If the enable secret password is used it supercedes the enable password.


    7. Which of the following statements about switching methods is true?
    Cut through switching examines the destination address (first 16 bytes after the preamble) and then forwards the frame.
    Fragment free switching examines the first 16 Bytes (Collision Window), runs a CRC check and then forwards the frame.
    Fragment free switching examines the first 64 Bytes (Collision Window), runs a CRC check and then forwards the frame.
    Cut through switching examines the destination address (first 8 bytes after the preamble) and then forwards the frame.
    Answer\Explanation
  • Fragment free switching examines the first 64 Bytes (Collision Window), runs a CRC check and then forwards the frame.

    It may be considered, that if there is not a problem with the first 64 Bytes then the rest of the frame is OK.
    With Cut Through switching only the destination address is read and the frame is immediately forwarded. This will have the lowest latency of the three switching methods, but the latency is always constant. This is often times referred to as reading the preamble of the frame or the first 8 bytes.


    8. Which of the following sets of routing protocols matches the correct administrative distances correctly?
    RIP 100, IGRP 120
    RIP 120, IGRP 100
    IGRP 110, RIP 120
    RIP 110, BGP 100
    Answer/Explanation
  • RIP 120, IGRP 100

    The following table represents administrative distances.
    Directly connected device --- 0
    Static route ------------------ 1
    EIGRP ---------------------- 90
    IGRP ----------------------- 100
    OSPF ---------------------- 110
    RIP ------------------------- 120
    bad news ------------------- 255


    9. IGRP (Interior Gateway Routing Protocol) is Cisco propietary, and was developed to overcome of the problems that were associated with RIP, which used hop counts as the only metric. Which of the following would be the default metric for IGRP?
    Bandwidth and line load.
    Bandwidth and line delay.
    Line delay and hops.
    Reliability, load, and MTU (Maximum transmission unit).
    Answer\Explanation
  • Bandwidth and line load.

    IGRP uses a total of 5 metrics, Line delay, bandwidth, reliability, line load and MTU (Maximum transmission unit). As the default, IGRP uses bandwidth and line delay. In either case it is referred to as a composite metric.
    Bandwidth and line delay are metrics that are used by IGRP but only bandwidth is a default.


    10. Which of the following commands would be used to turn terminal editing off at a Cisco router?
    router#terminal no editing
    router(config)#terminal no editing
    router# no terminal-editing
    router#no terminal editing
    router(config)#no terminal editing
    Answer/Explanation
  • router#terminal no editing

    When Terminal editing is turned on it enables the use of keyboard shortcuts as:

  • Ctrl+A to move the cursor to the beginning of the line.
  • Ctrl+E to move the cursor to the end of the line.

    If terminal editing is turned off then the terminal editing command may be used to turn it back on. These keyboard shortcuts are also referred to as Advanced editing features.



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