Streaming Protocols
There are two primary protocols for transmitting data over the Internet. TCP (transmission Control Protocol) and UDP (User Datagram Protocl). UDP is more suited to streaming because, unlike TCP is does not include error checking. This allows for a continuous stream of one-way data to be transmitted efficiently. Occasionally data packets will be lost although for streaming the odd packet lost is not very important.
Using these protocols, Real Networks pioneered RTSP, the Real Time Streaming Protocol in 1996. This has been used by Real Server, and it’s successor Helix Server as well as being adopted by Apple in producing it’s Quick Time Streaming Server and the open source Darwin Server. Both of these will use UDP by default, but can be configured to transfer over TCP.
Similarly Microsoft has created their own protocol and called it MMS (Microsoft Media Services). Again MMS will use UDP as the preferred transfer protocol, fail over to TCP where necessary and finally will attempt to transfer via http over TCP.
Streaming over http will work and is often the only way to stream through firewalls, although it is not ideal. HTTP (Hyper Text Transfer Protocol) was created to transfer discreet pieces of data as opposed to a continuous stream. It can be used for small files, but is more prone to packet loss, and unable to cope with large numbers of concurrent streams.
Add comment August 8th, 2005