An Overview of Cloud Based Content Delivery Networks: Research Dimensions and State-of-the-Art - Transactions on Large-Scale-Data-and Knowledge-Centered Systems XX - page 147

Management Console to register their origin servers with Amazon CloudFront. When
the customer has more than one server, he/she can use URL pattern matching to nd

which origin server has the content, and the customer can assign one of those origin
servers as the default server. The most signi

s CloudFront is that
it can be co-operated with several other Amazon Cloud Services. The architecture of
interactions between Amazon CloudFront and other AWS services is presented in Fig. 5 .
One of the major difference between Rackspace Cloud Files and Amazon CloudFront is
that Rackspace utilizes Akamai CDN service that offers 219 CDN edge locations
worldwide compared to only 32 CDN edge locations offered by Amazon. The Cloud-
Front enables handing of dynamic content while delivering web content that change for
each end-user. It uses the concept of URL pattern matching which has to be de

cant feature of Amazon '

ned
for the dynamic content being served to control the cache behaviour. When a URL
match succeeds for a dynamic content request, the corresponding cache behaviour is
invoked.

5.3 MetaCDN

MetaCDN [ 11 ] is another content delivery provider that offers two kinds of CDN
services: one for static content (e.g., websites) acceleration, and another for live mul-
timedia streaming. Unlike other CDN providers that have their own global distributed
system, MetaCDN take advantage of existing storage clouds and compute technology to
support its own services. Contrary to cloud providers such as Amazon and Rackspace
that offer diverse kind of additional services using their own infrastructure, MetaCDN
offers its services by integrating the offerings from several other public cloud providers
worldwide, thereby having in excess of 120 edge locations across the world for static
content delivery. In case of live streaming, they also have more than 40 edge servers
located around the world. As a consequence, MetaCDN is clearly illustrates the power
and value of combining the Cloud with the CDN for optimized content delivery over the
Internet. Figure 6 presents an overview of MetaCDN architecture [ 11 ].
The MetaCDN platform uses connectors to interface with public cloud storage
providers such as Amzaon S3, Limelight networks. The connector has the basic sets of
operations that are supported by most cloud storage providers. The MetaCDN also have
a number of core components responsible for functioning of the service. These include
the MetaCDN manager, QoS monitor, Allocator, Database and Load redirector. The
allocator selects the optimal service provider. The QoS monitor keeps track of cloud
storage performance and the CDN Manager tracks each user s current deployments.

The database is used to store vital user and cloud storage mapping information and

'

nally the Load Redirector is responsible for distribute end-user requests to appropriate
POP servers. The MetaCDN system also provides user interfaces and APIs to con gure

system via the web and programmatically.

5.4 Limelight Orchestrate: Limelight Networks

Limelight [ 13 ] is one of the biggest CDN providers in the world and offers services
such as cloud storage, web acceleration and media delivery. There are some typical