But service providers aren't the whole caching story. Indeed, a few years ago the first caching products to come to market were software-only and ran on UNIX. The most widely used and notable of these products is the freely available, open-source Squid project, originally funded by the U.S. National Science Foundation. Since then Squid, and other software-only caches, has been developed for many different operating systems, including Linux and even OS/2.
Squid served as the basis for a commercial product from Inktomi called Traffic Server. Inktomi has continued to expand its product line with a series of content distribution management tools it purchased earlier in the fall of 1999 from WebSpective Software. This notion of managing content is an important aspect of the overall caching universe, and can help improve latency by adding intelligent storage of frequently used page objects in the cache. Inktomi also bought shares in service provider InterNAP Network Services Corp. and has announced a deal with Intel Corp. to sell its software on Intel computers running Sun Microsystems Inc. Solaris, moving beyond the company's software-only roots and providing less-expensive solutions. Look for Inktomi to continue to broaden its caching product line through further acquisitions.
In addition to Squid, there are software-only caches from the major operating system/Web server vendors themselves. Novell Inc.'s Internet Caching System along with Netscape Communications Corp.'s and Microsoft Corp.'s Proxy Servers, each augment the company's Web server software products and are primarily designed to work in conjunction with their respective Web servers. This means more choices for your caching needs, and the ability to match the right server operating system with the existing level of expertise in your organization with these operating systems. It also means more competition and, hopefully, lower prices for future caching products.
The software-only caches are a good first step into the caching universe. They are relatively inexpensive (or free, in the case of Squid and its variants), easy to set up and configure, and don't require much in the way of new hardware. If you already have a UNIX, NetWare, or NT Web server, you can run the caching server as another application on these existing servers and manage the caching part of the server as just another task for managing the entire server. For small networks or workgroups you can run them on existing file or Web servers, and you don't have to learn your way around a new operating system. The downside is a lack of scalability and flexibility in terms of tuning these caches to specific networks and needs.
These software-only caches are best suited to improving the browsing experience for your own users. As I mentioned above, they can save local copies of frequently requested Web pages, freeing up both the time it takes to bring these pages across the Internet and the bandwidth of your outbound Internet connection as well.
If you require scalability and flexibility, the next step up is to buy one of the prepackaged caching servers. These typically combine some type of UNIX or NetWare, software, and hardware to deliver better performance and ease of set up. They use commonly available parts, such as Intel processors and PC-style hard disks, to keep the costs down.
The prepackaged market used to be the exclusive province of UNIX. In the past few months, however, Novell has come on strong and expanded its OEM relationships to combine its caching server software with traditional PC server hardware to create prepackaged caching servers. Again, this means more choices and competition with the UNIX world as well as increased comfort for those IT managers who have stuck with Novell these many years and still have NetWare expertise in house. These products include Dell Computer Corp.'s Internet Caching servers, Compaq Computer Corp.'s TaskSmart, Quantex Microsystems Inc.'s WebXL, and Australia-based Microbits' Intelli-App.These products resemble the traditional PCs sold by these vendors, but are exclusively caching devices. In other words, the caching servers can't run Windows applications or function as traditional NetWare file servers. Novell has also enabled its caching server software to work with service vendors Akamai and Edgix, an indication that it intends to be a major player in this market and that users can have a choice of products to use with these service provider networks in the future. Given Novell's strong OEM relationships, it is worth taking a careful look, particularly for low-cost caches that will serve smaller networks. Typically, Novell servers sell for under $5,000.