Internetworking Layer (IP) (Back to all quizzes)

  1. What is the goal of the Internetworking layer?

    Move packets across multiple hops from a source to destination computer
    Move packets across a single physical connection
    Deal with web server failover
    Deal with encryption of sensitive data

  2. How many different physical links does a typical packet cross from its source to its destination on the Internet?

    1
    4
    15
    255

  3. Which of these is an IP address?

    0f:2a:b3:1f:b3:1a
    192.168.3.14
    www.khanacademy.com
    @drchuck

  4. Why is it necessary to move from IPv4 to IPv6?

    Because IPv6 has smaller routing tables
    Because IPv6 reduces the number of hops a packet must go across
    Because we are running out of IPv4 addresses
    Because IPv6 addresses are chosen by network hardware manufacturers

  5. What is a network number?

    A group of IP addresses with the same prefix
    The GPS coordinates of a particular LAN
    The number of hops it takes for a packet to cross the network
    The overall delay packets experience crossing the network

  6. How many computers can have addresses within network number "218.78"?

    650
    6500
    65000
    650000

  7. How do routers determine the path taken by a packet across the Internet?

    The routes are controlled by the IRG (Internet Routing Group)
    Each router looks at a packet and forwards it based on its best guess as to the correct outbound link
    Each router sends all packets on every outbound link (flooding algorithm)
    Each router holds on to a packet until a packet comes in from the destination computer

  8. What is a routing table?

    A list of IP addresses mapped to link addresses
    A list of IP addresses mapped to GPS coordinates
    A list of network numbers mapped to GPS coordinates
    A list of network numbers mapped to outbound links from the router

  9. How does a newly connected router fill its routing tables?

    By consulting the IANA (Internet Assigned Numbers Authority)
    By downloading the routing RFC (Request for Comments)
    By contacting the Internet Engineering Task Force (IETF)
    By asking neighboring routers how they route packets

  10. What does a router do when a physical link goes down?

    Throws away all of the routing table entries for that link
    Consults the Internet Map (IMAP) service
    Does a Domain Name (DNS) looking for the IP address
    Sends all the packets for that link back to the source computer

  11. Why is it good to have at least a "two-connected" network?

    Because routing tables are much smaller
    Because it removes the need for network numbers
    Because it supports more IPv4 addresses
    Because it continues to function even when a single link goes down

  12. Do all packets from a message take the same route across the Internet?

    Yes
    No

  13. How do routers discover new routes and improve their routing tables?

    Each day at midnight they download a new Internet map from IMAP
    They periodically ask neighboring routers for their network tables
    They randomly discard packets to trigger error-correction code within the Internet
    They are given transmission speed data by destination computers

  14. What is the purpose of the "Time to Live" field in a packet?

    To make sure that packets do not end up in an "infinite loop"
    To track how many minutes it takes for a packet to get through the network
    To maintain a mapping between network numbers and GPS coordinates
    To tell the router the correct output link for a particular packet

  15. How does the "traceroute" command work?

    It sends a series of packets with low TTL values so it can get a picture of where the packets get dropped
    It loads a network route from the Internet Map (IMAP)
    It contacts a Domain Name Server to get the route for a particular network number
    It asks routers to append route information to a packet as it is routed from source to destination

  16. About how long does it take for a packet to cross the Pacific Ocean via an undersea fiber optic cable?

    0.0025 Seconds
    0.025 Seconds
    0.250 Seconds
    2.5 Seconds

  17. On a WiFi network, how does a computer get an Internetworking (IP) address?

    Using the DHCP protocol
    Using the DNS protocol
    Using the HTTP protocol
    Using the IMAP protocol

  18. What is Network Address Translation (NAT)?

    It looks up the IP address associated with text names like "www.dr-chuck.com"
    It allows IPv6 traffic to go across IPv4 networks
    It looks up the best outbound link for a particular router and network number
    It reuses special network numbers like "192.168" across multiple network gateways at multiple locations

  19. How are IP addresses and network numbers managed globally?

    There are five top-level registries that manage network numbers in five geographic areas
    IP addresses are assigned worldwide randomly in a lottery
    IP addresses are assigned by network equipment manufacturers
    IP addresses are based on GPS coordinates

  20. How much larger are IPv6 addresses than IPv4 addresses?

    They are the same size
    IPv6 addresses are 50% larger than IPv4 addresses
    IPv6 addresses are twice as large as IPv4 addresses
    IPv6 addresses are 10 times larger than IPv4 addresses

  21. What does it mean when your computer receives an IP address that starts with "169.."?

    Your connection to the Internet supports the Multicast protocol
    The gateway is mapping your local address to a global address using NAT
    There was no gateway available to forward your packets to the Internet
    The gateway for this network is a low-speed gateway with a small window size

  22. If you were starting an Internet Service Provider in Poland, which Regional Internet Registry (RIR) would assign you a block of IP addresses.

    ARIN
    LACNIC
    RIPE NCC
    APNIC
    AFRNIC
    United Nations