OPTICODEC-PC INTRODUCTION
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Figure 1-7: Icecast2 Server/Client Transports
HTTP — Web Servers
HTTP on web servers has the following properties:
•
It is commonly called a fast start or progressive download stream.
•
HTTP uses TCP/IP protocol to ensure that all streaming packets are delivered,
retransmitting if necessary. TCP is optimized for guaranteed delivery of data,
regardless of its format or size. For example, if your browser or client media
player realizes that it is missing a data packet from the server, it will request a
resend of that packet. Resend requests take time, take up more bandwidth,
and can increase the load on the server. If the network is congested, you could
begin to use more bandwidth for resends than for the media content itself.
TCP is not designed for efficient real time delivery or careful bandwidth con-
trol, but for accurate and reliable delivery of every bit.
•
HTTP does not attempt to stream in real time. To stream in real time, the
bandwidth of the network must be greater than the data rate of the stream-
ing content. If there is not enough bandwidth to transmit the streaming con-
tent in real time, streaming by HTTP allows the client to store the data locally
and play the content after enough has arrived.
•
HTTP is a good solution for slow, unreliable network connections; it ensures
complete media content delivery.
•
Most firewalls, routers, and network configuration schemes will pass HTTP.
•
HTTP cannot be used for live streaming.
•
HHTP provides no control over streaming content. Users cannot move to any
point in a file or clip without downloading the entire file first.
•
Because it uses TCP/IP, HTTP does not make efficient use of server resources.
Accordingly, it does not perform as well as UDP/IP under heavy server loads.
•
Beware of the copyright protection issues with on-demand file delivery, as us-
ers will be downloading your content to their computer and could easily redis-
tribute it without your permission.
