Method for caching and delivery of compressed content in a content delivery network

Abstract

A content delivery network (CDN) edge server is provisioned to provide last mile acceleration of content to requesting end users. The CDN edge server fetches, compresses and caches content obtained from a content provider origin server, and serves that content in compressed form in response to receipt of an end user request for that content. It also provides “on-the-fly” compression of otherwise uncompressed content as such content is retrieved from cache and is delivered in response to receipt of an end user request for such content. A preferred compression routine is gzip, as most end user browsers support the capability to decompress files that are received in this format. The compression functionality preferably is enabled on the edge server using customer-specific metadata tags.

Description

[0001] This application is a division of Ser. No. 10 / 194,043, filed Jul. 11, 2002. [0002] This application contains subject matter protected by copyright.BACKGROUND OF THE INVENTION [0003] 1. Technical Field [0004] The present invention relates generally to techniques for selectively storing content in a compressed form in a content delivery network edge server cache and for serving the content to an end user browser. [0005] 2. Description of the Related Art [0006] A content delivery network (“CDN”) is a collection of content servers and associated control mechanisms that offload work from Web site origin servers by delivering content on their behalf to end users. A well-managed CDN achieves this goal by serving some or all of the contents of a site's Web pages, thereby reducing the customer's costs while enhancing an end user's browsing experience from the site. In operation, the CDN uses a request routing mechanism to locate a CDN content server close to the client to serve each r...

AI Technical Summary

Benefits of technology

[0011] A technical advantage is provided by selectively compressing given content provider content as it is received (from an origin server) for caching at a CDN edge server, and / or selectively delivering given content in a compressed format from the edge server to a requesting end user browser. These techniques provide for effective last mile acceleration of content delivery in a CDN. Preferably, the edge server utilizes a publicly available compression utility such as gzip (GNU zip), although any convenient utility may be used. In one embodiment, the edge server has a first routine running on its forward side, i.e., the side that connects the edge server to one or more content provider origin servers. The first routine receives uncompressed content from a content provider origin server and selectively compresses that content to make more efficient use of the edge server's cache space. A second routine runs on the server's client side, i.e., the side that connects the edge server to requesting end user browsers. The second routine compresses content that has been cached in an uncompressed form so that such content can be delivered by the edge server (in such format) to the requesting end user browser. According to a technical advantage of the invention, preferably the routines are selectively controlled by customer-specific metadata supplied to the edge server.

[0012] In a preferred embodiment, compression metadata is defined for given compressible file types. A first metadata tag controls the edge server to take uncompressed content from an origin server and to apply the first routine to compress the content, thereby allowing the edge server to make more efficient use of its cache space. When a request for such content is received at the edge server, it is typically served as-is, namely, in the same compressed form in which it was cached. A second metadata tag controls the edge server to simply cache content in its uncompressed form (if cacheable) and, using the second routine, to compress the content when a request for compressed content is received at the edge server. Preferably the first and second routines are gzip. Because the majority of browsers in use today support gzipped content, content associated with the first or second metadata tags is delivered to the end user in a compressed form to provide last mile accelerated delivery.

[0013] Preferably, compression metadata is applied to compressible file types, e.g., those with a MIME type such as HTML, cascading style sheets, and the like. The benefits of compression for such content are significant. Typically, page sizes are reduced to roughly ¼-th of their original sizes, significantly reducing the transfer time to the end user.

[0014] The present invention provides an improved CDN edge server that fetches, compresses and caches content obtained from a content provider origin server, and / or compresses content on-the-fly as it is being delivered. These features preferably are enabled using simple metadata as applied to specified files, directories, host names or any other constraints.

[0015] The foregoing has outlined some of the more pertinent features of the present invention. These features should be construed to be merely illustrative. Many other beneficial results can be attained by applying the disclosed invention in a different manner or by modifying the invention as will be described.

Problems solved by technology

While browsers have had the capability to decompress content for years, most servers do not for various reasons, primarily due to issues involving compatibility, processor workload and complexity of content management.

While content delivery network service providers (CDNSPs) have developed and implemented techniques for accelerating delivery of content between origin server sites and the CDN edge servers, delivery over the so-called “last mile” (from the ISP at which the edge server is located to the end user) has not been adequately addressed.

Images