Caching is growing in popularity with the ISPs

Within the last few months Cable & Wireless, Concentric Network, Exodus Communications and PSINet have started deploying Inktomi's Traffic Server network cache system.

@Home Networks and Ameritech.net actually have Traffic Servers already deployed throughout their networks. Why are so many ISPs jumping on the network caching bandwagon? Because bandwidth isn't cheap and preserving any portion of it is key to the long-term goals of most ISPs.

Network caching essentially brings frequently accessed Web pages to the edge of an ISPs network. This reduces the amount of bandwidth being used to access a popular Web site that may be hosted on a server that's on the other side of the country from where the user is based. Traffic Servers let ISPs set up geographical content distribution and traffic surge protection by redirecting users to another server.

Clearly, caching is beneficial to ISPs, but users also benefit. If content is brought closer to users, then they should actually be able to receive information more quickly on a network with caching than without. But while caching has its good points, there is no substitution for heavy duty bandwidth. Not yet anyway.

Denise Pappalardo is a senior editor for Network World, covering ISPs, VPNs and related topics. Reach her at denisep@nww.com.