HTTP
Streaming
HTTP
streaming is a mechanism for sending data from a
Web server to a Web browser in response to an event.
HTTP Streaming is achieved through several common
mechanisms.
In
one such mechanism the web server does not terminate
the response to the client after data has been served.
This differs from the typical HTTP cycle in which
the response is closed immediately following data
transmission.
The
web server leaves the response open such that if
an event is received, it can immediately be sent
to the client. Otherwise the data would have to
be queued until the client's next request is made
to the web server. The act of repeatedly queing
and re-requesting information is known as a Polling
mechanism.
Typical
uses for HTTP Streaming include market data distribution
(stock tickers), live chat/messaging systems, online
betting and gaming, sport results, monitoring consoles
and Sensor network monitoring.
MMS
- Microsoft Media Services
Microsoft's
streaming server uses the Microsoft Media Services
(MMS) protocol (also called NetShow Services) to
transfer unicast data. MMS can be transported via
UDP or TCP. If the Windows Media Player client cannot
negotiate a good connection using MMS over UDP,
it will resort to MMS over TCP. If that fails, the
connection can be made using a modified version
of HTTP (always over TCP). This is not as ideal
for streaming as MMS over UDP, but ensures connectivity
nonetheless.
The
default port for MMS is 1755.
RTSP
- Real Time Streaming Protocol
The
Real Time Streaming Protocol (RTSP), developed by
the IETF and published in 1998 as RFC 2326, is a
protocol for use in streaming media systems which
allows a client to remotely control a streaming
media server, issuing VCR-like commands such as
"play" and "pause", and allowing
time-based access to files on a server.
Some
RTSP servers use RTP as the transport protocol for
the actual audio/video data. Many RTSP servers use
RealNetworks's proprietary RDT as the transport
protocol.
PNM/PNA
The
first version of RealAudio used a proprietary protocol
called PNA or PNM to send streaming audio data.
RealNetworks later switched to the IETF standardized
Real Time Streaming Protocol (RTSP) but they use
RTSP only to manage the connection.
RTMP
- Real Time Messaging Protocol
Real
Time Messaging Protocol (RTMP) Is a proprietary
protocol developed by Adobe Systems (formerly developed
by Macromedia) that is primarily used with Macromedia
Flash Media Server to stream audio and video over
the internet to the Adobe Flash Player client.
The
default connection port is 1935.
