DCCP (Datagram Congestion Control Protocol) is a new transport protocol designed for unicast applications. It offers an unreliable, bidirectional, point-to-point, end-to-end transport service. DCCP implements congestion control mechanisms to regulate the rate of data transmission, and an acknowledgement mechanism for received data. DCCP has been introduced as an alternative to TCP and UDP, for time-critical applications requiring techniques to adapt throughput to network conditions. References in square brackets are explained in the section Learn more.
Like TCP and UDP, DCCP is located at Layer 4 of the Internet's protocol layer reference model (figure 1). Protocol Data Units (PDUs), known as packets, can contain either application data directly, or Real-time Transport Protocol (RTP) packets .