因特网流协议（IPv5）是一个资源协议，被称为因特网流协议(ST)，目的是提供服务质量（QoS），支持多媒体在因特网上实时传输。需要注意的是：IPv6与IPv5无关，IPv5也已嵌入至IPv4。

The Internet Stream Protocol (ST and later ST-II) is a family of experimental protocols first defined in Internet Experiment Note IEN-119 (1979), and later substantially revised in RFC 1190 (ST-II) and RFC 1819 (ST2+).

The Internet Stream Protocol family was never introduced for public use, but many of the concepts available in ST are similar to later Asynchronous Transfer Mode protocols and can be found in Multiprotocol Label Switching (MPLS). They also presaged Voice over IP.