TCP sends an ACK (ACKnowledgement) to the sender for every received packet.
Not quite. TCP receivers only need to send ACKs when they have received enough data to fill the sliding window. That may be every packet, every other packet (the recommended by the RFC) or more.
Not quite. TCP receivers only need to send ACKs when they have received enough data to fill the sliding window. That may be every packet, every other packet (the recommended by the RFC) or more.