a reliable internet
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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 - PowerPoint PPT PresentationTRANSCRIPT
A Reliable InternetA Reliable Internet
J. Bradley ChenJ. Bradley Chen
Chief Technology OfficerChief Technology Officer
Appliant, Inc.Appliant, Inc.
© Appliant, Inc. All rights reserved.
The ProblemThe Problem
One of these things is not like the other…One of these things is not like the other…
Reliability
© Appliant, Inc. All rights reserved.
What’s the difference?What’s the difference?
Compared to “mature” consumer Compared to “mature” consumer technologies, the Internet demonstrates:technologies, the Internet demonstrates: poor reliabilitypoor reliability high complexity high complexity a pervasive lack of accountabilitya pervasive lack of accountability
Many of these differences are related to Many of these differences are related to the the federatedfederated nature of the Internet. nature of the Internet.
© Appliant, Inc. All rights reserved.
Accountability in a FederationAccountability in a FederationWho’s responsible for your web experience?Who’s responsible for your web experience?
Example: www.altavista.com from @HomeExample: www.altavista.com from @Home AltavistaAltavista
web and content serversweb and content servers Lots of other equipmentLots of other equipment
Akamai (image service) Akamai (image service) Doubleclick (ad service)Doubleclick (ad service) Level3 (Altavista middle-mile)Level3 (Altavista middle-mile) Sprint (Akamai middle-mile)Sprint (Akamai middle-mile) Alternet (Doubleclick middle-mile)Alternet (Doubleclick middle-mile) InterNAP (Doubleclick first-mile)InterNAP (Doubleclick first-mile) @Home (last-mile network link)@Home (last-mile network link) Microsoft IE5.5 Browser on Windows NTMicrosoft IE5.5 Browser on Windows NT
© Appliant, Inc. All rights reserved.
Accountability: SolutionAccountability: Solution
Option 1: Test-BasedOption 1: Test-BasedPeriodic experiments test the correct Periodic experiments test the correct operation along a specific path through the operation along a specific path through the system.system.
Option 2: Monitor-BasedOption 2: Monitor-BasedObservation of ongoing system activity Observation of ongoing system activity exposes system behavior and irregularities.exposes system behavior and irregularities.
These options are complementary.
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A Superficial ComparisonA Superficial ComparisonCoverage Repeatability Data Volume
Test Only covers problems included in tests
Complete coverage is extremely expensive
Good Low to moderate
Monitor Can reveal any problem for any page delivered to an end-user
Marginal coverage during periods of low activity
Marginal for managing availability
Good to poor; depends on traffic volume
Can be huge!
Monitoring Example:Monitoring Example:
Appliant’s Lateral Line ServiceAppliant’s Lateral Line Service
© Appliant, Inc. All rights reserved.
Internet cloudInternet cloud
Appliant Lateral LineAppliant Lateral Line
End-usersEnd-users
Internet cloudInternet cloud
FirewallFirewall
LoadLoadbalancersbalancers
WebWebserversservers
AppAppserversservers
DataDatabasebase
Data CenterData Center
SummarizeSummarize ReportReport AlertAlert ConfigureConfigure Collect dataCollect data CommunicateCommunicate
CachingCachingProxyProxy
Net
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System ArchitectureSystem Architecture
Data Center
Web User
RM
ON
Legend: LLCore
Data Store
Schema+SP
Web Server
SMON
APPD
Transport
Business
Data Manager
Rules
OnlineReporting
Config
OfflineReporting
Gen
Customer Site
Export
© Appliant, Inc. All rights reserved.
© Appliant, Inc. All rights reserved.
Case StudyCase Study
A CDN ProblemA CDN Problem
27 January 200127 January 2001
Case StudyCase Study
Documenting CDN PerformanceDocumenting CDN Performance
July 2001July 2001
© Appliant, Inc. All rights reserved.
Parting ThoughtsParting Thoughts A reliable Internet is possible essential.A reliable Internet is possible essential. Progress demands more accountability.Progress demands more accountability.
The Internet is a federation.The Internet is a federation. Without accountability, it could be a long wait.Without accountability, it could be a long wait.
Analysis of data from detailed system Analysis of data from detailed system monitors can expose many of the problems monitors can expose many of the problems we overlook today.we overlook today.
© Appliant, Inc. All rights reserved.