Week 8

It is the responsibility of a routing algorithm to determine a datagram's next hop information.

True

It is the responsibility of a routing algorithm to find a datagram's path through a network.

True

NAPT devices translate IP address and port numbers. (True)

True

The "Identification" header field is unchanged by IP datagram fragmentation.

True

The "traceroute" application (on Windows) receives ICMP messages. (T/F)

True

The path MTU is the smallest MTU on a path from sender to receiver. (T/F)

True

When a destination host's IP fragment timer expires, it drops all accumulated fragments corresponding to that timer. (T/F)

True

The "traceroute" application (on Windows) sends ICMP messages by default.

True (Sends UDP by default on other OS with option to use ICMP echo requests)

Given an internet represented as a weighted undirected graph, the shortest path between node X and node Y is the path that...

has the smallest sum of edge weights

The path MTU is the largest MTU on a path from sender to receiver. (T/F)

False

The transport-layer header is encapsulated in every IP datagram fragment.

False

The Internet Protocol (IP) implements congestion control. (T/F)

False

Suppose that a 2200-byte datagram (identification #40) must transit a network which has a 660-byte MTU. Assume the minimum IP and TCP header sizes, i.e., the IP header is 20 bytes and the TCP header is 20 bytes. 1. How many fragments are created? 2. How many bytes of application data are carried in the first fragment? 3. How many bytes of application data are carried in the second fragment? 4. How many bytes of application data are carried in the last fragment? 260 bytes 5. What is the identification number of the second fragment? # 6. What is the fragment offset in the last fragment?

1. 4 2. 620 3. 640 4. 260 5. 40 6. 240

Upon encountering a router with the following routing table: Prefix Match Port 10011110 00011110 10001111 0 10011110 00011110 10001111 000 1 10011110 00011110 10001111 01 2 10011110 00011110 10001110 0001 3 Default 4 A datagram with the destination IP address 158.30.142.90 would be routed to Port _____ .

4

The Internet Protocol (IP) implements timing controls. (T/F)

False

For a TCP/IP datagram leaving a home network through a NAPT device, which of the following header fields (IP and/or TCP) are altered? (Check all that apply) Destination IP address Source IP Address Header Checksum Destination Port Upper Layer Protocol Source Port Identification

Checksum Source IP Address Source Port

For a TCP/IP datagram coming into a home network through a NAPT device, which of the following header fields (IP and/or TCP) are altered? (Check all that apply) Upper Layer Protocol Source Port Header Checksum Identification Destination Port Destination IP address Source IP Address

Destination Port Destination IP address Checksum

If an IP datagram is fragmented into 1000-byte fragments, and later encounters a link with an 800-byte MTU, a special procedure (other than standard IP fragmentation) must be used.

False

Network address translation alters IP to add new IP addresses. (T/F)

False

Network address translation is strictly a Layer-3 protocol.

False

The IP header is encapsulated in IP datagram fragments.

False

The network layer manages communications from _____ to ______.

Host-to-host

Which of the following are benefits of a datagram network? Connection states are preserved. Less overhead than a VC network. Guaranteed timing. Guaranteed bandwidth. Faster delivery.

Less overhead than a VC network Faster delivery

The largest amount of data, in bytes, which can be accommodated by a particular network, link, or physical-layer is called the [a].

Maximum Transmission Unit (MTU)

In network graph terminology, [a] represent routers.

Nodes

In a datagram network, the responsibilities of the network layer include: congestion control reliable delivery payload error correction packet routing connection setup/takedown flow control host-to-host communication packet forwarding

Packet routing Packet forwarding host-to-host communication

In network graph terminology, a [a] from A to B is the set of edges to traverse to reach B from A for the lowest total cost.

Shortest Path

If hosting a server inside a NATed network, how do clients outside the NAPT router connect to the server? (Check all that apply) Using Universal Plug and Play (UPnP) By using the NAPT devices IP address, and a port number pre-configured to correspond to the server. By using the server's local IP address. Through a connection relay service

Using Universal Plug and Play By using the NAPT devices address.... Through a connection relay service

In network graph terminology, [a] represent costs.

Weights

In network graph terminology, [a] represent direct connections between routers.

edges

Re-assembly of fragmented IP datagrams is handled by...

the destination host

The "time to live" field in a modern IPv4 datagram header specifies...

the number of remaining hops before the datagram is dropped