Recommendation ITU-T H.248.82 defines a package to allow ITU-T H.248 controlled media gateways to support explicit congestion notification (ECN). ECN is a mechanism to provide indications of incipient congestion affecting a Real-Time Protocol (RTP) stream to a receiver and, usually, to a sender. ECN when used with an RTP stream over UDP uses the RTP control protocol to provide feedback of ECN congestion markings to an RTP sender. The mechanism allows senders and/or receivers to react in order to reduce congestion in real-time communications. This Recommendation only describes the use of ECN in RTP over UDP streams.