Computer Networks Questions & Answers – UDP MCQ أسئله شبكات بالأجابات الجزء الرابع والثلاثون

Computer Networks Questions & Answers – UDP

1. Which of the following is false with respect to UDP
a) Connection-oriented
b) Unreliable
c) Transport layer protocol
d) All of the mentioned

Answer: a
Explanation: UDP is an unreliable, connectionless transport layer protocol.

2. Return value of the UDP port “Chargen” is
a) String of characters
b) String of integers
c) Array of characters with integers
d) Array of zero’s and one’s

Answer: a
Explanation: Chargen with port number 19 returns string of characters.

3. Beyond IP, UDP provides additional services such as
a) Routing and switching
b) Sending and receiving of packets
c) Multiplexing and demultiplexing
d) Demultiplexing and error checking

Answer: d
Explanation: UDP is a simple protocol which provides demultiplexing and error checking.

4. The main advantage of UDP is
a) More overload
b) Reliable
c) Less overload
d) Fast

Answer: c
Explanation: UDP is an unreliable, connectionless transport layer protocol and uses minimum overload.

5. Port number used by Network Time Protocol(NTP) with UDP is
a) 161
b) 123
c) 162
d) 124

Answer: b
Explanation: Port number used by Network Time Protocol with UDP is 123.

6. what is the header size of UDP packet?
a) 8 bytes
b) 8 bits
c) 16 bytes
d) 124 bytes

Answer: a
Explanation: The fixed size of the UDP packet header is 8 bytes.

7. The port number is “ephemeral port number”, if the source host is ……
a) NTP
b) Echo
c) Server
d) Client

Answer: d
Explanation: If the source host is the client, the port number in most cases will be ephemeral port number.

8. “Total length” field in UDP packet header is the length of
a) Only UDP header
b) Only data
c) Only checksum
d) UDP header plus data

Answer: d
Explanation: Total length is the 16 bit field which contains the length of UDP header and the data.

9. Correct expression for UDP user datagram length is
a) UDP length = IP length – IP header’s length
b) UDP length = UDP length – UDP header’s length
c) UDP length = IP length + IP header’s length
d) UDP length = UDP length + UDP header’s length

Answer: a
Explanation: A user datagram is encapsulated in an IP datagram. There is a field in the IP datagram the defines the total length. There is another field in the IP datagram that defines the length of the header. So if we subtract the length of a UDP datagram that is encapsulated in an IP datagram, we get the length of UDP user datagram.

10. The field used to detect errors over the entire user datagram is
a) UDP header
b) Checksum
c) Source port
d) Destination port

Answer: b
Explanation: Checksum field is used to detect errors over the entire user datagram.

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