Reliable UDP
wanweibaike Reliable User Datagram Protocol
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(原始) 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.
NOTE:
一、诞生时间是比较早的
二、"too primitive"的意思是UDP太弱了，不符合需求
三、显然 RUDP 是介于 UDP 和 TCP 之间的
Implementations
In order to ensure quality, it extends UDP by means of adding the following features:
1、Acknowledgment of received packets
2、Windowing and flow control
3、Retransmission of lost packets
4、Over buffering (Faster than real-time streaming)
NOTE:
一、接收了部分TCP的特性
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.