Inktomi to Web: Got cache?

Inktomi's network traffic server has always included the capacity to cache heavily requested Internet content, moving it off servers and onto proxies located at the edge of an Internet service provider's network. The result has been faster, more fault-free downloads for users and for service providers, protection from traffic spikes such as those generated by the Starr report. Now Inktomi has announced Traffic Server 2.0, a refinement produced through a partnership the company entered into last August with streaming media specialist RealNetworks (Telephony, Aug. 24, page 16).

Still in beta tests with ISP Digex, Traffic Server 2.0 caches static content and streaming media. When the first client requests content, Traffic Server streams it into the cache while it's sent off to the client. Subsequent requests get pulled directly out of the cache. RealNetworks uses a particular codec for each line speed, making the clarity at 28.8 kb/s different from that at ISDN or digital subscriber line rates. Traffic Server can distinguish among download speeds and provide proper clarity to each client.

A live streamed event can't be cached, but Traffic Server 2.0 can still help. "When lots of people want to see the same live content, we can split that content stream out to tens or hundreds of clients," said Peter Galvin, director of traffic servers for Inktomi. "This avoids a lot of congestion over the Internet. Even when all those people trying to view the Clinton testimony finally got a connection, all the people taking individual signals off the servers made the quality of that video very grainy in many cases."

The new version of Traffic Server includes added support for Web hosting. Many ISPs started out providing standard dial-up Internet access; when that became a commodity, they moved to providing business access and more dedicated services. "Now that that's commoditized as well, they've moved into Web hosting," Galvin said. "We suspect over the next 12 months that will be commoditized as well, and ISPs will look for additional value-added services"-something that traffic caching could free up the bandwidth to do.

Web hosting features include reverse proxy implementation, in which the network servers sit behind a bank of traffic servers that aggregate their content. When huge spikes in traffic occur, rather than building out large individual servers, ISPs can build a central cache farm in reverse proxy to handle peak demands.

Traffic Server 2.0 has added protocols useful to ISPs. HTTP 1.1 is becoming popular with Web publishers for its more detailed control of things such as header instructions. The new server works with HTTP 1.1, reading header information on content that gives instructions such as, "Expire this page in five minutes."

The new Inktomi server is the first to provide network news transport protocol (NNTP) for caching Usenet news transparently within the network, Galvin said. Most ISPs use a T-1 across the backbone to receive these feeds and distributed NNTP servers across their networks to store these news articles as a service to a small subset of their users. "It's a loss leader for consumer ISPs," Galvin said. "They have to carry it for the sophisticated customers who like Usenet news groups, but the majority of their users read a very small part of this content." Distributed caches can replace a series of larger, more costly NNTP servers receiving very large traffic feeds.