Question

TCP headers and segmentation (B) 10. Which of the following flelds in the UDP header Is NOT found in the TCP header? source port destination port checksum length 11. The value of the acknowledgement field in a TCP segment defines Number of bytes to retransmit Number of bytes to receive Starting point of next bytes to receive in sequence Total number of bytes left 12. Suppose Host A sends one segment with sequence number 38 and 4 bytes of data over a TCP connection to Host B. The acknowledgement number included in the same segment must be 42. True or False? □ True False

Answer 1

Solution 10)

A TCP header consist of 10 required fields of 20bytes and an optional data section of 40 bytes

The following are the fields in TCP

a) Source TCP port number (2 bytes)
b) Destination TCP port number (2 bytes)
c) Sequence number (4 bytes)
d) Acknowledgment number (4 bytes)
e) TCP data offset (4 bits)
f) Reserved data (3 bits)
g) Control flags (up to 9 bits)
h) Window size (2 bytes)
i) TCP checksum (2 bytes)
j) Urgent pointer (2 bytes)
k) TCP optional data (0-40 bytes)

On the other hand UDP have 8 byte header field as follows

a) Source port number (2 bytes)
b) Destination port number (2 bytes)
c) Length of data (2 bytes)
d) UDP checksum (2 bytes)

Ans: Length field in UDP is not present in TCP

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Solution 11)

The acknowledement field in a TCP segment defines the starting point of next bytes for a receiver or expected to send by the sender

Ans: Starting point of next byte to receive in sequence

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Solution 12)

Ack number denotes the next expected byte from the sender. The ack number have nothing to do with the sequence number .

Ans: False