Section 3.3

Question 1

Name 3 features of UDP:

Answer 1

1.“no frills,” “bare bones” Internet transport protocol
2. “best effort” service
3. connectionless

Question 2

What are some advantages of UDP?

Answer 2

1. no connection establishment delay (which can add RTT delay)
2. simple: no connection state at sender, receiver
3. small header size
4. no congestion control

Question 3

Name UDP sender actions:

Answer 3

1. UDP is passed an application-layer message
2. UDP determines UDP segment header fields values
3. UDP creates UDP segment
4. passes segment to IP, IP forwards IP datagram to IP host

Question 4

Name UDP receiver actions:

Answer 4

1. UDP receiver receives segment from IP
2. checks UDP checksum header value
3. extracts application-layer message
4. demultiplexes message up to application via socket

Question 5

True or False: On the sending side, the UDP sender will take each application-layer chunk of data written into a UDP socket and send it in a distinct UDP datagram. And then on the receiving side, UDP will deliver a segment’s payload into the appropriate socket, preserving the application-defined message boundary.

Answer 5

True

Question 6

What is found in a UDP segment header?

Answer 6

Length, Internet checksum, destination port number and source port number

Question 7

Why is the UDP header length field needed?

Answer 7

Because the payload section can be of variable length, and this lets UDP know where the segment ends.

Question 8

Over what set of bytes is the checksum field in the UDP header computed over?

Answer 8

The entire UDP segment, except the checksum field itself, and the IP sender and receive address fields