Content Delivery Network Providers

A content delivery network, commonly referred to as a content distribution network, is a data collecting computer system that distributes data over various nodes of the network. This service is provided by different companies and individuals serving different clientèle. Before discussing the providers, it is important to understand what CDN is and what its benefits are.
CDN benefits
A content delivery network has various benefits. A few notable ones are:
• Capacity
The limit or capacity of a CDN is much greater than the network backbone capacity. This increased capacity allows many users to work concurrently.
• Loads
The interconnectivity loads can be decreased significantly if the edge server of a CDN system is placed strategically to lower the delivery cost.
• Latency/Packet loss
Since a CDN transmits content over the TCP and UDP connections, placing them close to the edge networks helps in reducing latency and packet loss. This allows for fast delivery of the content as the content is closer to the network. This reduces jitter, improves the quality of streaming, and increases security and reliability and so on.
• Outage
As the CDN has dynamic distribution ability, it keeps delivery data even if there is a large network or power outage.
• Load
A CDN allows the operator to have increased control over the asset delivery and network load. It optimizes the performance and provides real-time logs regarding the load.

CDN Technology
A CDN is made up of different nodes which are installed on various backbones in different global locations. Each node coordinates with another node to respond to the user’s request. The data is transmitted through these nodes to the servers over the Internet. Thus the process of delivery takes place. The nodes help in optimizing the delivery process reducing bandwidth costs, increasing the availability of content for access from anywhere around the globe and improving the performance for the user.
A CDN can consist of many servers depending on the architecture being used or needed. Some CDN architectures are made up of thousands or servers and nodes on various remote PoPs. Algorithms are used to pass the message along for optimized performance.
Location of a CDN also plays an important in the optimized delivery process. The closer a CDN is located; the better will be the performance of delivery.

CDN Networking techniques
The basic purpose of a content delivery network is to enhance the delivery of the end-to-end data by distributing the data over various intelligent applications. These intelligent applications use different methods to optimize the delivery content. As a result, closely integrated overlays are used that can serve as web cache, server load balancer, request routes and content services.
As a web cache, a content delivery networks server stores occasionally requested and accessed data. This helps in reducing the bandwidth, latency and response time.
The next technique, server load balancing, allows a content delivery network to balance the load between software and hardware such as web switch, content switch and multilayer switch. A CDN usually is installed with a ‘4-7’ switch which allows to create a service node or a content cluster to balance the load between different CDN servers.

Commercial vs. Free Content Delivery Networks
Commercial CDN – A content delivery network is a service that is available commercially. A commercial CDN offers a high quality experience, as the service is backed by a company that provides high bandwidth, high security and low latency. Furthermore, unlike a free content delivery network, a commercial CDN has the capacity to spread static content of websites over various locations and servers to offer optimal performance.
Free CDN – Peer to peer technology is mostly utilized by free content delivery network providers as it lowers the load on the server for transferring files between servers. The quality of the service is not as high-quality as the one provided by a commercial CDN. In addition, static web content is not transmitted by a free CDN over different locations.
Different commercial CDN providers have different pricing ranges for content delivery network architecture. The price is usually based on the expected web traffic that a website may generate. Pricing CDN architecture is a complex process with each company having its own guidelines. There are however, a few standard factors that are taken into consideration when setting a price for CDN architecture or service:

  • Traffic variation and distribution
  • Number of surrogate servers
  • Cost of bandwidth
  • Size of content to be replicated
  • Stability and reliability of a CDN system
  • Security concerns

Types of CDN services
A content delivery network is designed to offer three basic services: simple caching service, remote delivery of different applications and hardware load balancing globally. Simple caching or web caching service is that in which frequently accessed information is stored on a CDN. This makes retrieving the data easy when the bandwidth is low.
As an application provider, it allows computer technicians and network technicians to provide cloud computing services using SaasS technology.
Another service that a CDN can provide is of a load-balancer. When the server content is being distributed and duplicated from different locations, a CDN reduce or manage the load.

Types of content delivered
Streaming, caching and progressive downloading is achieved using commercial delivery networks as it is the best technology for delivering rich media content over the Internet. HD video streaming works best with a content delivery network. This serves to decrease the latency, reduce wait times and buffering.
Downloading speed is also increased as a CDN can balance and download the delivery route to the end user such as new software downloads, game downloads, audio, HD video and so on.
A CDN is an optimal solution for caching content that although static is occasionally accessed such as online shopping, social networking sites, travel sites and hosting sites.

CDN Service providers
Content delivery network providers are the suppliers of the delivery of digital services to the users from the media and entertainment companies. The CDN providers have set up their own private networks on top of the Internet. These networks provide users with enhanced service quality and scalability. Media companies as well as the entertainment companies need a solution that may deliver their digital content to their users in as little time as possible. The CDN providers offer this solution. They offer the companies their networks to improve the performance of the delivered content.
The list of CDN service providers is a long one as it is categorized in four parts:
Free CDN providers

• MediaBlog
• PeerCast
• PPLive
• Coral CDN
• PPStream
• CoBlitz

Commercial CDN Providers

• Akamai Technologies
• AT&T
• CDNetworks
• Internap
• LimeLight Networks
• Windows Azure CDN
• Cotendo

Telco CDN providers

• AT&T
• BT Group Bell Canada
• Orange
• SingTel
• Reliance Globalcom
• Tata Communications
• Verizon

Commercial P2P CDN Providers

• Internap
• Pando Networks
• Bit Torrent Inc
• Octoshape

Content Delivery Network Providers
Here are few top content delivery network providers in the world.
Akamai Technologies

Akamai Technologies is the leading content delivery network provider in the world. The company uses the technology to transparently mirror the content of websites including CSS, HTML and software downloads. Sometimes it mirrors content such as graphics, video, audio and animation from servers of the customers. Although the domain name is the same, the IP address refers to a server on Akamia rather than a server of the customer. The architecture is designed in a way that the Akamai server automatically picks up depending on the content type and the location of the user.
The benefit of such a system is that the user can receive the content faster from the Akamai server that is located near the user. This allows the user to have fast download time and high network security in regards to congestion and outages. Furthermore, Akamai offers services in personalized and dynamic content, content cache, streaming media and J2EE-compliant applications.
Akamai Technologies own about 60 domains, but the servers mostly use primary domains such as:
• (Akamai’s corporate domain)
• (Akamai’s content delivery domain)
• & (Akamai’s DNS servers)
• Akamai part of Facebook content distribution network
Akamai Technologies has a huge customer base both commercial and individuals. Commercial customers include AMD, Facebook, Adobe Systems, Netflix, JC Penny, Yahoo and Miles Kimball.

Limelight Networks
One of the top competitors of Akamai is Limelight Networks. Situated in Tempe, Arizona, the company operates a fiber-optic network globally. The services offered by the company enables the users to avoid sending media files over the busy Internet and deliver the same files to the end-users using CDN technology. The major clients of Limelight Networks include Disney, DreamWorks, EA Sports, Microsoft, MSNBC, BBC, Xbox and Toyota.
Amazon Cloud Front
Amazon Web Services offers a content delivery network solution under the name of Amazon CloudFront. The service is on pay-as-you-go basis which was launched in 2008. Since then, the CDN service has gained much popularity especially in the European region.
The Amazon CloudFront has CDN servers located around the world for better and faster user experience. Servers are located in Asia (Japan, Singapore and Hong Kong), Europe (Germany, the Netherlands, United Kingdom and Ireland) and United States (New York, Los Angeles and Washington).
Amazon CloudFront is in competition with Akamai and Limelight Networks providing unmatchable service.
NetDNA is a content delivery network provider and an application delivery network provider. The company is located in Los Angeles, CA. Operating since 2009 under the leadership of Ben Neumann and Chris Ueland, the company has grown quickly to make a reputable name in the industry. Recently the company has launched two brands HDDN and MaxCDN which is a self-service, pay-as-you-use CDN service and a video-on-demand solution service. The most popular service of the company is MaxCDN. It caters the small and medium sized companies. The company, NetDNA, works in collaboration with large enterprises such as Packet Exchange, Garmin, ReadWriteWeb, Flowplayer, and Mashable.
Velocix is another leading content delivery network provider that offers advanced architectural network solutions to different customers. It is a network appliance based solution that enables content service providers to deploy and delivery their own digital media such as quality streaming, faster download times and much more. Velocix provides untapped services to the content delivery providers enabling them to leverage their services in the market.
Windows Azure CDN
Taking the industry by storm is the new technology of Windows known as Windows Azure CDN. The Windows Azure content delivery network offers enhanced user performance and reliability by caching the user applications and static objects at strategically selected locations. The Azure CDN offers best experience to deliver the content to the end users who are located away from the source of the content.
The Windows Azure CDN delivers many products to users such as Zune videos, Windows Update and Bing Maps. The content is delivered using different Windows Azure resources such as Windows Azure compute roles and Windows Azure storage. The service delivers content including downloadable object files (software, media files and documents), web objects (JavaScript, CSS and JPG), real time applications and streams, Internet delivery components (database queries, DNS and routes) and much more. The pricing is based on pay-as-you-use method.

CDN providers vs. traditional ISP providers
Internet Service Providers (ISPs) were considered very powerful before the concept of content delivery networks. The advantages that were once limited to the ISPs have now shifted with the CDN providers who offer P2P CDN solutions with many variations.

ISP providers have to install heavy infrastructure to provide their services which are not considered of high-quality as compared to CDN technology. A CDN technology does not require any large investments as it is inexpensive to build CDN architecture. It can provide the best performance as it capitalizes on the end –nodes’ bandwidth.