ITPEC FE Subject A April 2026 Question 25

Flow control — lets the receiver limit how fast the sender transmits.

Its purpose is to protect a slow receiver from a fast sender: the receiver signals how much it can accept (for example through a window or a stop-and-wait acknowledgement) and the sender waits until there is room.

Answer (c)

Why not others:
- (a) Congestion control — reacts to overload inside the network, not to the receiver's capacity, and lives mainly at the transport layer
- (b) Error control — detects and retransmits corrupted or lost frames; it says nothing about pacing
- (d) Media access control — decides which station may transmit on a shared medium, a question of who goes next rather than how much

Key rule: Flow control protects the receiver, congestion control protects the network. The two are easy to swap because both slow the sender down.

AI-generated — may contain errors