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A Reliable Internet. J. Bradley Chen Chief Technology Officer Appliant, Inc. The Problem. Reliability. One of these things is not like the other…. What’s the difference?. Compared to “mature” consumer technologies, the Internet demonstrates: poor reliability high complexity
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A Reliable Internet J. Bradley Chen Chief Technology Officer Appliant, Inc.
The Problem Reliability One of these things is not like the other…
What’s the difference? Compared to “mature” consumer technologies, the Internet demonstrates: • poor reliability • high complexity • a pervasive lack of accountability Many of these differences are related to the federated nature of the Internet.
Accountability in a FederationWho’s responsible for your web experience? Example: www.altavista.com from @Home • Altavista • web and content servers • Lots of other equipment • Akamai (image service) • Doubleclick (ad service) • Level3 (Altavista middle-mile) • Sprint (Akamai middle-mile) • Alternet (Doubleclick middle-mile) • InterNAP (Doubleclick first-mile) • @Home (last-mile network link) • Microsoft IE5.5 Browser on Windows NT
Accountability: Solution • Option 1: Test-Based Periodic experiments test the correct operation along a specific path through the system. • Option 2: Monitor-Based Observation of ongoing system activity exposes system behavior and irregularities. These options are complementary.
Monitoring Example: Appliant’s Lateral Line Service
Summarize • Report • Alert • Configure • Collect data • Communicate Data Center End-users Appliant Lateral Line Net Caching Proxy Data base Load balancers App servers Internet cloud Internet cloud Firewall Web servers
Web Server SMON RMON APPD Gen Config Offline Reporting Online Reporting Schema+SP Data Store System Architecture Customer Site Web User Data Center Business Rules Transport Data Manager Export Legend:LL Core
Case Study A CDN Problem 27 January 2001
Case Study Documenting CDN Performance July 2001
Parting Thoughts • A reliable Internet is possible essential. • Progress demands more accountability. • The Internet is a federation. • Without accountability, it could be a long wait. • Analysis of data from detailed system monitors can expose many of the problems we overlook today.