Which of the following key features is used by TCP in order to regulate the amount of data sent by
a host to another host on the network?

A.
Sequence number

B.
TCP timestamp

C.
Congestion control

D.
Flow control

Explanation:

Flow control is the process of regulating the amount of data sent by a host to another host on the
network. The flow control mechanism controls packet flow so that a sender does not transmit more
packets than a receiver can process. TCP uses a sliding window flow control protocol. In each
TCP segment, the receiver specifies in the receive window field the amount of additional received
data (in bytes) that it is willing to buffer for the connection. The sending host can send only up to
that amount of data before it must wait for an acknowledgment and window update from the
receiving host.
Answer option A is incorrect. TCP uses a sequence number for identifying each byte of data.
Answer option B is incorrect. TCP timestamp helps TCP to compute the round-trip time between
the sender and receiver.
Answer option C is incorrect. Congestion control concerns controlling traffic entry into a
telecommunications network, so as to avoid congestive collapse by attempting to avoid
oversubscription of any of the processing or link capabilities of the intermediate nodes and
networks and taking resource reducing steps, such as reducing the rate of sending packets. It
should not be confused with flow control, which prevents the sender from overwhelming the
receiver.