What is ECN (explicit congestion notification)?

Explicit Congestion Notification (ECN) is characterized in RFC 3168 (2001). It is an augmentation to the Internet Protocol and to the Transmission Control Protocol. ECN permits start to finish notification of network congestion without dropping packets. ECN is utilized between two ECN-empowered endpoints when the underlying network framework likewise upholds it. ECN diminishes the quantity of packets dropped by a TCP association, which, by keeping away from a retransmission, lessens latency and jitter.