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 145

nd that who should be responded for that among the Cloud provider, the CDN
provider and the Customer when something goes wrong. As a consequence, it would be
necessary to build an accountable Cloud system which means it is easy to

nd whose
false when some mistakes happen in such kind of Cloud system. Implementing data
mining algorithms to analyze the log system is a good choice to address this problem.

Cloud Load Balancer. The Cloud load balancer provides the customers the flexibility
to manage their content delivery strategy. This service enables customers to specify
content delivery policies based on real-time conditions and user targets. The typical
cloud load balancing technology manages the customers

c and makes
decisions of where to route it. When a node in the Cloud system fails, a health check
process will remove it from rotation to keep maximum availability of the whole system.
The Cloud load balancer service should follow the pay-as-you-go model as well in term
of the hours the customers use, number of current connections and bandwidth [ 7 ].

' application traf

Cloud Orchestrator. Cloud orchestration service offers enhanced flexibility and
elasticity of CCDN as it manages public and private cloud resources using the pay-as-
you-go model. Cloud orchestration operations include: (i) production: create and edit;
(ii) storage: uploading and scaling of storage space; (iii) keyword-based content tagging
and searching and (iv) distribution: streaming and downloading. At Cloud service level,
the orchestrator capabilities span across a range of operations such as selection,
assembly, deployment of cloud resources to monitoring their run-time QoS statistics
(e.g., latency, utilization, and throughput). The orchestrate supports deployment, con-

guration and monitoring of content and cloud resources deployed across hybrid cloud
platforms using web-based widgets. These widgets hide the underlying complexity
related to cloud resources and provide an easy do-it-yourself interface for content
management. The cloud orchestration service is also responsible to manage the cloud
resources based on service providers SLAs.

5 Existing Cloud-Based CDNs

The current landscape of CCDNs leverages the flexibility of the cloud to easily and
quickly distribute content across the internet. The CCDNs landscape diversi es into two

primary forms namely web site content distribution and media distribution. Web site
content focuses mostly on serving static pages with a combination of text and other
media content while the media delivery CCDNs are dedicated to deliver high speed video
form content providers such as Netflix. The majority of the system use the architecture
presented in Fig. 3 with proprietary implementation of cloud storage architecture,
security, DNS, load balancer, CDN orchestrator and indexing mechanisms. In this sec-
tion, we will analyse the current state-of-the are in commercial and academic/research
based CCDN solutions.