Which protocol provides flow control in network communications?

TCP, or Transmission Control Protocol, is the protocol that provides flow control in network communications. Flow control is a crucial feature that manages the rate of data transmission between sender and receiver, ensuring that the sender does not overwhelm the receiver's capability to process incoming data.

TCP incorporates a mechanism known as sliding window protocol, which dynamically adjusts the amount of data that can be sent before requiring an acknowledgment from the receiver. This capability allows TCP to maintain a steady flow of data without causing congestion, ensuring that packets are sent and received reliably and in order.

On the other hand, protocols like UDP (User Datagram Protocol) do not provide flow control as they are designed for applications that need faster transmission without the overhead of ensuring reliability and order. ICMP (Internet Control Message Protocol) serves a different purpose, primarily used for diagnostic and error messaging. HTTP (Hypertext Transfer Protocol), while it does utilize TCP as its transport layer, operates at a higher level of the protocol stack without explicit flow control features as part of its primary function. This context highlights why TCP is the appropriate answer for a protocol that inherently includes flow control mechanisms.