KC 7

Consider the three subnets in the diagram below. What is the maximum # of interfaces in the 223.1.3/29 network?

8

Consider the pattern of red and green packet arrivals to a router's output port queue, shown below. Suppose each packet takes one time slot to be transmitted, and can only begin transmission at the beginning of a time slot after its arrival. Indicate the sequence of departing packet numbers (at t = 1, 2, 3, 4, 5, 7, 8) under FCFS scheduling. Give your answer as 7 ordered digits (each corresponding to the packet number of a departing packet), with a single space between each digit, and no spaces before the first or after the last digit, e.g., in a form like 7 6 5 4 3 2 1).

?

Which of the following fields occur ONLY in the IPv6 datagram header (i.e., appear in the IPv6 header but not in the IPv4 header)? Check all that apply. 128-bit source and destination IP addresses. The IP version number field. The time-to-live (or hop limit) field. The header checksum field. The flow label field. The header length field. The options field. The upper layer protocol (or next header) field.

?

Which one of the following operations is not performed by NAT.? Generating ACKs back to the TCP sender and then taking responsibility for reliably delivery the segment to its destination, possibly using a non-TCP reliable data transfer protocol. On an outgoing datagram, changing the transport-layer port number of the transport-layer segment inside a datagram received from the LAN side of the NAT. On an incoming datagram from the public Internet side of a NAT, changing the destination IP address of a datagram to a new destination IP address that is looked up in the NAT table, and (possibly after other actions), sending that IP datagram on to the LAN side of the NAT. On an outgoing datagram, changing the source IP address of a datagram received from the LAN side of the NAT

a

Which of the following quality-of-service guarantees are part of the Internet's best-effort service model? Check all that apply. Guaranteed delivery from sending host to receiving host. Guaranteed delivery time from sending host to receiving host. In-order datagram payload delivery to the transport layer of those datagrams arriving to the receiving host. A guaranteed minimum bandwidth is provided to a source-to-destination flow of packets None of the other services listed here are part of the best-effort service model. Evidently, best-effort service really means no guarantees at all!

none

What protocol (or protocols) constitutes the "thin waist" of the Internet protocol stack? Check all that apply. HTTP TCP IP Ethernet DNS WiFi

c

Match the names of the principal router components (A,B,C,D below) with their function and whether they are in the network-layer data plane or control plane.

???A are input ports, operating primarily in the data plane B is the switching fabric, operating primarily in the data plane C are output ports, operating primarily in the control plane D is the routing processor, operating primarily in the data plane

Longest prefix matching. Consider the following forwarding table below. Indicate the output to link interface to which a datagram with the destination addresses below will be forwarded under longest prefix matching. (Note: The list of addresses is ordered below. If two addresses map to the same output link interface, map the first of these two addresses to the first instance of that link interface.) 11001000 00010111 00010010 10101101 11001000 00010111 00011000 00001101 11001000 00010111 00011001 11001101 10001000 11100000 00011000 00001101 11001000 00010111 00011000 11001111 11001000 00010111 00010001 01010101 11001000 00010111 00011101 01101101

This is the first destination address in the list that maps to output port 0. This is the first destination address in the list that maps to output port 1. This is the first destination address in the list that maps to output port 2. This is the first destination address in the list that maps to output port 3. This is the second destination address in the list that maps to output port 1. This is the second destination address in the list that maps to output port 0. This is the second destination address in the list that maps to output port 2.

Check all of the statements below about where (in the network) the network layer is implemented that are true. The network layer is implemented in hosts at the network's edge. The network layer is implemented in routers in the network core. The network layer is implemented in Ethernet switches in a local area network. The network layer is implemented in wired Internet-connected devices but not wireless Internet-connected devices.

a b

Which of the following statements is true regarding an IP address? (Zero, one or more of the following statements is true). An IP address is associated with an interface. If a host has more than one interface, then it has more that one IP address at which it can be reached. If a router has more than one interface, then it has more that one IP address at which it can be reached. It is not necessary for a device using the IP protocol to actually have an IP address associated with it.

a b c

What is meant by an IP subnet? (Check zero, one or more of the following characteristics of an IP subnet). A set of device interfaces that can physically reach each other without passing through an intervening router. A set of devices that always have a common first 16 bits in their IP address. A set of devices that have a common set of leading high order bits in their IP address. A set of devices all manufactured by the same equipment maker/vendor.

a c

For each of the actions below, select those actions below that are primarily in the network-layer data plane. The other actions that you don't select below then correspond to control-plane actions. Looking up address bits in an arriving datagram header in the forwarding table. Computing the contents of the forwarding table. Moving an arriving datagram from a router's input port to output port Monitoring and managing the configuration and performance of an network device. Dropping a datagram due to a congested (full) output buffer.

a c e

What is meant by saying that DHCP is a "plug and play" protocol? The host needs to "plug" (by wire or wirelessly) into the local network in order to access ("play" in) the Internet No manual configuration is needed for the host to join the network. The network provides an Ethernet jack for a host's Ethernet adapter.

b

What is the purpose of the Dynamic Host Configuration Protocol? To configure the interface speed to be used, for hardware like Ethernet, which can be used at different speeds. To obtain an IP address for a host attaching to an IP network. To get the 48-bit link-layer MAC address associated with a network-layer IP address. To configure the set of available open ports (and hence well-known services) for a server.

b

Which of the following network devices can be thought of as a "middlebox"? Check all that apply. IP router Network Address Translation box WiFi base station HTTP load balancer HTTP cache SDN controller

b d e