In computer networking, the Reliable User Datagram Protocol (RUDP) is a transport layer protocol designed at Bell Labs for the Plan 9 operating system. It aims to provide a solution where UDP is too primitive because guaranteed-order packet delivery is desirable, but TCP adds too much complexity/overhead. In order for RUDP to gain higher Quality of Service, RUDP implements features that are similar to TCP with less overhead.
In order to gain ensure quality, it extends UDP by adding the following additional features:
Acknowledgment of received packets
Windowing and flow control
Retransmission of lost packets
Overbuffering (Faster than real-time streaming)
RUDP is not currently a formal standard, however it was described in an IETF internet-draft in 1999. It has not been proposed for standardization.
