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HOW DOES STREAMING WORK?

SERVERS WITH  A  SMILE?

Although streaming technology can start to seem mighty complex mighty fast, it's all 

really based on this simple model:

If you are a do it yourselfer who is not 

going to be streaming very much media 

Web Server

to very many people, your Web server 

1 

The end user selects 

2 

The Web server relays the 

and media server might just be different 

a media fi le, causing 

request to the media server.

processes (handled by different server 

software applications) running on 

a request to be sent 

Media Server

the same machine.

to the Web server.

If you are already going into techno  

phobic shock at the very mention of 

Client

 clients  and  servers,  don't despair, 

read on  The techies who invent these 

things love to confuse the rest of 

us with tricky terminology, just to 

3 

The Media server 

make sure we keep them around.

streams the media fi le 

While the term  server  sometimes 

back to the end user's computer.

refers to hardware, as in  That old server 

4 

The client, or  player,  decodes 

is collecting dust,  it may also mean 

and plays back the media fi le.

software, as in  We installed a new Web 

server on that computer today.  Both 

uses actually refer to the same princi 

WHERE DO STREAMS COME FROM?

ple a server is a solution designed to 

receive requests from a third party and 

respond by delivering, or  serving up,  

Streaming media architectures 

a particular type of data. This process 

An architecture is an interdependent system comprised of a variety 

is also known as a  transaction. 

of components that all work together to perform certain functions. 

Requests are sent to a server by a  client.  

Streaming media architectures are comprised of encoding and trans 

Again, the term client may be used to 

mission methods, server software, and players (client software). 

refer to a PC (hardware) or to a software 

Currently, the three most popular streaming media architectures 

application. A good example of a client is 

are RealMedia, Windows Media, and QuickTime. 

a Web browser, which is software installed 

on a PC that functions as a client to Web 

There are also a few interesting alternatives available, including archi 

servers. When the client receives the data 

tectures based on Java applets that do not require the end user to have 

it has requested from the server, it may 

a proprietary player (or plug in) installed. Instead, an ultra light Java 

further process and/or display the data. 

applet delivers an ephemeral player to the end user's browser, enabling 

Media  players  are software clients that 

playback for the duration of the streaming session, after which the 

process and play back video and/or audio.

player is discarded. While such java based players are usually less intru 

Any computer on which the appropriate 

sive than proprietary players some even virtually transparent they 

server software has been installed can 

typically do not offer the full range of end user controls made available 

function as a server. But typically, when 

by the proprietary players.

a piece of hardware is dedicated to 

that role, it is made up of high grade 

Currently, however, and for a variety of technology and business reasons which 

components that will deliver reliable 

are beyond the scope of this document, the streaming market is dominated by three 

24/7/365 availability.  

architectures: RealMedia, Windows Media, and QuickTime. The unfortunate result is 

that there are now three parallel standards that do not work together. Imagine what it 

If you reach the point where you are 

serving so many streams to so many users 

might have been like if, when television fi rst hit the airwaves, each of the three major 

that, in order to handle the traffi c, you 

networks required a different device to translate their signal into video and audio each 

need a dedicated media server (and you 

home would have needed an ABC television set, a CBS television set, and an NBC televi 

namic Medianamic Media

decide to handle your media hosting in 

y

sion set, if the household wanted to watch programs on every channel. That's essentially 

y

house rather than outsourcing), you will 

what the situation is, in today's streaming media marketplace. While there is some 

probably want what is known as an 

limited cross over in the players' ability to play back other architectures' formats, the 

 appliance server  or  network appliance.   

technology is so competitive, that end users cannot count on cross over capabilities 

A network appliance is server hardware 

obe Dobe D

working, as the formats rapidly evolve. This can be confusing and irritating for end 

with  factory installed  server software, 

dd

users, who must continually download the latest plug ins and then fi gure out which 

designed specifi cally for a specifi c type of 

AA

server function such as handling media.

to choose as the default player in their browser, based on which is being supported 

by the majority of their favorite content providers.

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