Engineering A Public Affairs Project Donna Liu, Executive Director UChannel, Princeton University Vivek Pai, Associate Professor CS Department, Princeton.

Engineering A Public Affairs Project

Donna Liu, Executive DirectorUChannel, Princeton University

Vivek Pai, Associate ProfessorCS Department, Princeton

UniversityCopyright Vivek Pai 2007. Permission is granted for this material to be shared for non-commercial, educational purposes, provided that this copyright statement appears on the reproduced materials and notice is given that the copying is by permission of the author. To disseminate otherwise or to republish requires written permission from the author.

October 26, 2007 - Educause 2

BBB.COM

WWW Service

client


Content Distribution Networks

BBB.COM

client server surrogate

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cache

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AAA.COM

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CCC.COM

redirector


Commercial CDN Companies

Many playersAkamai, Limelight, Level 3, …

CostsMonthly commitment(High) Premium over BWPossibly extra for spikes


Enter PlanetLab

ConsortiumUniversities, research labs, companies

ResourcesEach member contributes machines, BW

AccessBy joining, you get accounts everywhere

ProjectsExperiments, long-running services


PlanetLab Overview819 Nodes at 406 Sites


CoDeeN: Toward a Self-Healing Web

Goals:Improve all levels of Web infrastructureInteroperate where possibleDrive with real trafficFeed back measurementsRouting

Name Lookup

Data Transfer

Replication

Client

Security


CoBlitz Project

On-demand replication of large filesNo limit on file size

Using HTTP – standard clients & serversNo plugins, fewer support callsNo BitTorrent blocking, etc.

No preprocessing/staging neededInstant-on, immediate overload protection


CoBlitz

Agent CDNClient

CDN reverse caches the chunks!

CDN

CDNCDN

CDN ClientAgent

CDN

chunk1

chun

k1chunk2

chunk3

chunk2

chunk5

chunk5

chunk1

chunk1

chunk4 chunk4 chunk5

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k5

chunk1 chunk2

chunk3 chunk3

chunk4 chunk5

CDN = Redirector + Reverse Proxy


How To Use CoBlitz

Start with a regular URLNo password protectionAny standard Web serverOnly static content – no CGI, etcIdeally, unchanging

Add CoBlitz prefix – coblitz.codeen.orghttp://www.example.com/bigfilehttp://coblitz.codeen.org/www.example.com/bigfile


CoBlitz Content Restrictions

Domain ends in .eduNo restrictions

General public, not whitelistedNo html, images, audio, video – copyright issuesStill useful for ISOs, PDFs, etc.

Whitelisted – contact usNo restrictions


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Direct BitTorrent CoBlitz

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Median

CoBlitz Performance

CoBlitz users:UChannelCiteSeer digital libraryFedora Core LinuxMozarteumPlanetLab projects


UChannel CoBlitz Usage

Served directly

Served by CoBlitz


Browsers Versus RSS

Regular browsersDiurnal scheduleFlash crowds possible

RSS (Really Simple Syndication)Publishing via “feeds”“Feed readers” poll & grab new itemsPoll frequency ~1hr for always-on


UChannel Bandwidth Usage – 5min

Extremely sharp peaks


UChannel Bandwidth Usage – 1hr

Reasonable non-peak BW only 25 Mbps


UChannel Usage Statistics


Production QuestionsAre you stable?

Running 3 years, mostly 24/7No centralization – runs even when Princeton disconnected

How much BW available?Function of demand & participationMore PL members more BWMore CoBlitz usage less extra capacity

Service Level Agreements?Not on public PlanetLab


Fedora Core 6 Release – Public PL

Released 10am 10/24/061.4 Gbps peak, sustained 800+ Mbps


Limits on Current Deployment

Possibly outlast welcome (bandwidth)Keep going until PL members complainRegularly the #1 BW consumerSometimes more than rest combined

Exact BWs not under our controlShare resources on (overloaded) PLNo Africa coverage, spotty Australia


Polish TV Results – Private PL

New record: 3.3 Gbps aggregateAll links near 100% utilizationNow, weekly trials starting


Growth & Sustainability

Nonprofit usersCost-recovery modelBuy BW in bulk, pay for developersCheaper than CDNs, private BW purchase

For-profitsSpinning out tech as PlanetWorks LLCPrivate managed CoBlitz appliancesCost-effective beyond 10 Mbps


Example Cost-Recovery

$25K/month (aggregate) can buy1Gbps bandwidth8 locations, 3 machines/location1 support person

If there are 5-10 projects interested,let’s get in touch


Questions

[email protected]://codeen.cs.princeton.edu/

coblitz/

[email protected]://uc.princeton.edu

Engineering A Public Affairs Project Donna Liu, Executive Director UChannel, Princeton University Vivek Pai, Associate Professor CS Department, Princeton.

Documents

coblitz slide

redirector slide

combigfile slide

c c c c c c

coblitz prefix

www service client slide

educause8 coblitz project

standard web server