What Happened to IPV5 ??
ST (RFC1190)- A Proposed Internet Stream Protocol or IPV5
ST has been developed to support the efficient delivery of streams of packets to either single or multiple destinations in applications requiring guaranteed data rates and controlled delay characteristics. The motivation for the original protocol was that IP did not provide the delay and data rate characteristics necessary to support voice applications. ST is an internet protocol at the same layer as IP, see Figure 1. ST differs from IP in that IP, as originally envisioned, did not require routers (or intermediate systems) to maintain state information describing the streams of packets flowing through them. ST incorporates the concept of streams across the internet.
Every intervening ST entity maintains state information for each stream that passes through it. The stream state includes forwarding information, including multicast support for efficiency, and resource information, which allows network or link bandwidth and queues to be assigned to a specific stream. This pre-allocation of resources allows data packets to be forwarded with low delay, low overhead, and a low probability of loss due to congestion. The characteristics of a stream, such as a number and location of the endpoints, and the bandwidth required, may be modified during the lifetime of the stream. This allows ST to give a real-time application the guaranteed and predictable communication characteristics it needs, and is an excellent vehicle to support an application whose communications requirements are relatively predictable.
The ST packet header is not constrained to be compatible with the IP packet header, except for the IP Version Number (the first four bits) that is used to distinguish ST packets (IP Version 5) from IP packets (IP Version 4). The ST packets, or protocol data units (PDUs), can be encapsulated in IP either to provide connectivity (possibly with degraded service) across portions of an internet that do not provide support for ST or to allow access to services such as security that are not provided directly by ST.
The reason is that IPv5 doesn’t exist, It never made it to become one of the IP protocols. AS mentioned above, It was planned as a streaming protocol, and it got to its second version, ST2. Its packets had the IP version 5 ID but died as a draft. The big problem IPv5 had was that it used the same IPv4 addressing and had the same limited number of addresses. Before it was abandoned, IPv5 was comprehensively tested and various backbones were built. It was also released on several OS to check its compatibility. The only hurdle was it couldn’t generate enough IPv5 addresses. Part of its development went to the next version, and that is how IPv5 history finished.
Beginning of ST2
The first version of ST was published in the late 1970s and was used throughout the 1980s for experimental transmission of voice, video, and distributed simulation. The experience gained in these applications led to the development of the revised protocol version ST2. The revision extends the original protocol to make it more complete and more applicable to emerging multimedia environments. The specification of this protocol version is contained in Internet RFC1190 which was published in October 1990 [RFC1190].
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