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Ignite Technologies Content Delivery Network

Posted by Lead Maverick in Dallas-Fort Worth-Arlington, TX on Mar 12, 2008

Content Delivery Network
Ignite Technology

What is a Content Delivery Network?
A content delivery network or content distribution network (CDN) is a system of computers networked together across the Internet that cooperate transparently to deliver content (especially large media content) to end users. The first web content based CDNs were Sandpiper, Mirror Image and Skycache followed by Akamai and Digital Island, and Nortel.

Current Market Overview
Currently there are approximately 30 different types of Content Deliveryon the market. They all range in size, type, reach and reliability. The top CDN's are considered to be Akamai, Limelight Networks, & CDNetworks. According to a recent Tier1 Report It's expected that in 2008 over 79% of the global CDN market is divided among these 3 players. Other companies, such as EdgeCast Networks, Bitgravity, PantherExpress, Highwinds and others are just launching their services. Most CDN's are focused on Video Delivery within the US. Only few CDN's are capable of delivering content on a global scale. On a global scale, only Akamai, LimeLight Networks, and CDNetworks have the network deployed to deliver high performance in all major global markets.

Technology
CDN nodes are deployed in multiple locations, often over multiple backbones. These nodes cooperate with each other to satisfy requests for content by end users, transparently moving content behind the scenes to optimize the delivery process. Optimization can take the form of reducing bandwidth costs, improving end-user performance, or both.

The number of nodes and servers making up a CDN varies, depending on the architecture, some reaching thousands of nodes with tens of thousands of servers.

Requests for content are intelligently directed to nodes that are optimal in some way. When optimizing for performance, locations that can serve content quickly to the user may be chosen. This may be measured by choosing locations that are the fewest hops or fewest number of network seconds away from the requestor, so as to optimize delivery across local networks. When optimizing for cost, locations that are less expensive to serve from may be chosen instead. Often these two goals tend to align, as servers that are close to the end user sometimes have an advantage in serving costs, perhaps because they are located within the same network as the end user.

Some CDNs such as LimeLight Networks have created direct peering relationships with the major IP Providers and "eyeball networks". It is because of these peering relationships that LimeLight can deliver 85-90%+ of it's traffic directly over the end users ISP's network therefor bypassing the Internet entirely. There is simply no faster way to deliver content than this way.