Not to be outdone by Novell, a number of vendors have taken versions of UNIX to create their own prepackaged servers. These include Cobalt Networks Inc.'s Cache Cube, Eolian Inc.'s InfoStorm, PacketStorm Technologies' WebSpeed, Entera Corp.'s TeraNode, and Network Appliance Inc.'s NetCache. These servers are somewhat more expensive, ranging in price from $5,000 to $10,000, and offer the same kind of benefits as the Novell servers, only running on UNIX.
A second group of prepackaged servers bundles the Inktomi Traffic Server with a router, a server, or other network gear. This group includes products from Alteon Web Systems Inc., as well as Foundry Networks Inc.'s ServerIron.These products include something besides caching, such as load balancing or content switching, and are geared more toward larger networks and adding reliability and fail-safe operations to the caching equation. For example, to take advantage of the extra reliability found in Foundry's products, users will have to replace their existing network switches or routers and connect their Web, database, and other critical servers to its switch. And given these extra features, expect to pay $10,000 and up for these products.
Like the software-only caches, these prepackaged servers are great for workgroups and small corporations looking to improve the browsing experience for their users. They are also appropriate for smaller ISPs looking to save on outbound bandwidth.
One disadvantage of the prepackaged servers is they are still running a general-purpose operating system, either UNIX or NetWare. While both OSs have lots of benefits, neither was specifically designed for delivering the optimum caching performance. To get around this problem several vendors have developed their own caching appliances, which come with specialty operating systems that just do caching and nothing else. Companies in this market include CacheFlow Inc., InfoLibria Inc., Cisco Systems Inc., and Lucent Technologies.
Suitable for both internal corporate networks and service providers, these OSs come in a wide variety of sizes and capacities to match the network load. For example, CacheFlow's product line supports T1, 15Mb, 45Mb, and OC-3 speeds, with storage capacity ranging from four to 243 gigabytes. Specialty appliances are somewhat pricey, however, with typical models starting around $15,000. The appliances are similar to some of the more sophisticated prepackaged servers in that they do more than cache; they also do Web proxying, content management, and redundant network operations. In other words, they're more like complete systems for delivering more reliable Web content. The main difference is that the appliances typically run their own operating systems and caching algorithms, which have been developed to work together for the best caching performance. The appliances also have additional features that would not normally be found on general UNIX or NetWare servers. For example, CacheFlow's server can restart in seconds--important where power quality might be an issue.
Both the prepackaged and appliance vendors are after more serious Web server operators and take mainframe-like approaches to quality. For example, InfoLibria's server is designed as a fail-over router, Web proxy, and cache all rolled into one. Lucent's IPWorX WebCache line includes Web switching features from ArrowPoint Communications Inc. and Alteon, along with Lucent's own caching software. Foundry includes load balancing and Web content switching features, and adds the ability to support redundant links in case a cache server fails. This means that users can obtain some of the same benefits from the large-scale service provider networks such as Akamai and Sandpiper but do so in house by using the Lucent and ArrowPoint products. For corporations that don't want to outsource their Web applications to the caching service providers, either because of control, cost, or coverage issues, these are a good alternative.
Caching appliances are probably the best devices for improving the browsing experience for existing network users. They are designed to examine the packet streams and page structures and store the most frequent items locally, in a way to ensure that the freshest content is delivered to each browser.
Caching is still an evolving area. Look to see new players, new ideas, and new products in the months to come. But it is nice to have choices, particularly as you search for the best solution to match the size of your network, your budget, and your needs, whether you wish to improve the browsing experience for your own users or for external visitors to your Web site.IJ
About the author:David Strom was the founding editor-in-chief of Network Computing magazine and has written over a thousand articles for dozens of computer trade publications. He publishes Web Informant, a weekly guide to new Web technologies, trends, and services and is a frequent speaker at industry events including Next Generation Networks and Networld+Interop. He can be reached at firstname.lastname@example.org.