On Tuesday Amazon.com made good on its promise to enter the content delivery network business with a pay-as-you-go service that could undercut the offerings of established players such as Akamai and Limelight Networks.

The service, dubbed CloudFront, will pick up, transport,and deliver web content for commercial entities using a network of its servers.The purpose of a content delivery network (CDN) is to speed web performance.

Rather than leave the delivery of multimedia content such as sound files and video at the mercy of the untamed web, CDNs reroute traffic through strategically placed servers.

Amazon is coming in unlike rivals in that it will not require customers to sign long-term contracts. CloudFront customers will be charged based on usage.

CloudFront uses the same network and storage resources as Amazon’s other web services such as its Simple Storage Service (S3) and Elastic Compute Cloud (EC2).

S3 offers developers and companies a relatively inexpensive web storage infrastructure, while EC2 is Amazon’s cloud computing service.

Two months ago Seattle-based Amazon announced its plan to get into the CDN business, an already crowded market.

But with its extensive network of servers and datacenters used for internal applications, it was just a matter of time before Amazon would offer some of that content delivery capacity for rent.