Information Technology Reference
In-Depth Information
1.2.1 unicasting Video Streams
Unicast is the traditional method for delivering content to users. There are
two different setups for unicast video delivery, commonly called media
server farms and Content Delivery Networks (CDN).
1.2.1.1 Media Server Farms
In a media server farm [2], several expensive network servers are housed in
one location. There is a load balancer distributing user requests to differ-
ent servers in the farm. In addition to load balancing, another advantage of
such a setup is robustness. If any server breaks down, others will take over.
All servers in the farm share the same upload capacity. Applications like
YouTube and Webs-TV employ media server farms for content distribution.
A conceptual diagram of a media server farm is shown in Figure 1.4. In
such a setup, a company would need to purchase or lease high-end serv-
ers along with sufficient upload bandwidth. The cost of bandwidth in total
would be a lot higher than the fixed equipment. As population grows, a com-
pany would need to purchase more servers and pay for more bandwidth to
serve the users.
1.2.1.2 Content Delivery Networks (CDN)
Content providers who do not want to spend money on maintaining server
infrastructure use a CDN [16]. CDN companies, such as Akamai, own the
infrastructure, and the content providers, such as CNN, pay for the service of
delivering the video content to the users with the least possible delays.
Media server farm
Users
Figure 1.4
The media server farm.
