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Network Appliance
Need to show John Cleese's management training videos to your
corporation's management team, but can't get everyone in a room at the
same time? New technologies are allowing corporate intranet and Internet
users to access documents, videos, and other e-learning materials across
large distances. These new technologies are called Content Delivery
Networks (CDNs).
A CDN is a network that consists of a traditional intranet or Internet,
specialized devices for storage and caching, and applications for
distributing content to different parts of the network. The key to a CDN
is placement of rich data at the "edge" of the network, far from the
central servers and close to the people who are accessing the data. By
putting content close to the user, before the user requests it, there is
less interaction between the user's browser and the central Web server.
This reduces access times, network traffic, and the server's load,
resulting in better delivery of the content. The technology that sits at
the "edge" of the network can be a conventional file server, but
special-purpose caching appliances also provide this function with less
administrative overhead.
The CDN becomes even more effective when specialized devices called
filers are linked to the central server. Filers can efficiently store
multiple terabytes of data and can quickly serve this data when
required. To illustrate how a CDN might be deployed, think of a
corporate training center in Houston with offices in New York,
Los Angeles, and Tokyo. In Houston, filers store vast amounts of
content, the content is "pushed" to remote caches, and the caches in
each of the remote locations deliver the content locally. In addition to
efficient handling of data, the caching devices ensure high quality of
delivery (especially for video), dependable service, and support for
many media formats.
Network Appliance customers have implemented content delivery networks
for a variety of reasons, including:
- Live and on-demand video broadcasts of corporate events
- Live and on-demand video broadcasts of training
- Distribution of documents (reports, presentations, engineering files)
At Network Appliance, we use our own equipment in our internal content
delivery network. Network Appliance sells filers, caching appliances,
and content distribution applications, and we use our products to
deliver documents, video, and other media.
In the Technical Publications department at Network Appliance, we've
taken advantage of our own technology many times. Recently, we rented a
series of training videos. To view the videos, we could have required
all of the viewers to gather together for several hours. Given that it's
hard to get people together for a one-hour meeting, let alone several
hours of training, we streamed the videos. (Streaming is the technical
term for serving video data over a network.) People were able to watch
the videos in 20-minute segments from their desks whenever they had the
time. The quality was very crisp (no "Max Headroom" effect), and,
because it was easy to take in the content over several days, everyone
who needed the training was able to receive it. Even more recently, some
writers were too busy to attend the corporate All Hands meeting, so they
watched the live presentations from a corner of their monitors while
they worked to meet their deadlines. In fact, people in remote Network
Appliance offices always watch corporate presentations online, either in
real time or after the fact.
Content delivery using filers, caches, and distribution tools offers
several advantages over traditional Internets, including:
- Reduced network traffic to central servers
- Lower administration costs
- Specialized software for backups, mirroring, and scheduled movement of content from one part
of the network to another
- High availability
- Short access times
As more content, particularly streaming media, is delivered over
Internets and intranets, content delivery networks will play a larger
role in organizations responsible for providing the content.
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