the convergence of network computing...
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Copyright 1997, David G. Messerschmitt 3/5/97 1
The convergence of network The convergence of network computing and computing and
telecommunicationstelecommunications
David G. MesserschmittDavid G. Messerschmitt
University of California at BerkeleyUniversity of California at Berkeley
Copyright 1997, David G. Messerschmitt 3/5/97 2
TerminologyTerminology
Services
Bitways
Applications
Realizing the Information Future: The Internet and Beyond, Nat. Res. Council
ATM, IP, wireless, etc..
Audio, video, payment,directory, privacy keys, etc.
Video conferencing,voice and electronic mail,WWW browsing, etc.
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Telecommunications-computing Telecommunications-computing confusionconfusion
■■ Infrastructure blurringInfrastructure blurring–– Data, audio, video in Data, audio, video in ATM networkATM network
–– Data, audio, video in Data, audio, video in desktop computerdesktop computer
■■ Applications blurringApplications blurring–– Home banking by Home banking by DTMF and voice responseDTMF and voice response
–– Home banking by Home banking by desktop computer and desktop computer and modem or Internetmodem or Internet
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Types of applicationsTypes of applications
■■ User-to-user User-to-user
■■ User-to-information serverUser-to-information server
■■ User-to-user with information serverUser-to-user with information server
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User-to-information server exampleUser-to-information server example
World-wideweb browser
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User-to-user examplesUser-to-user examples
Shared whiteboard
Shared editor
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Taxonomy of networked Taxonomy of networked applicationsapplications
Video on demandWWW browsing
File transfer
TelephonyVideo conference
Electronic mailVoice mail
Immediate Deferred
User-to-informationserver
User-to-user
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Two architecturesTwo architectures
Client
Client
Client Server
Peer
Peer
Peer Peer
Peer
Peer
User-to-information serverUser-to-user
User-to-user
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Two architectures for user-to-user Two architectures for user-to-user applicationsapplications
Peer Peer
Client
Client
ServerComputerworldview
Telecomworldview
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Vertical to horizontal integrationVertical to horizontal integrationN
etw
ork/
serv
ice/
appl
icat
ion
Net
wor
k/se
rvic
e/ap
plic
atio
n
Net
wor
k/se
rvic
e/ap
plic
atio
nServices
Bitways
Applications
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Advantages of horizontal integrationAdvantages of horizontal integration
■■ Services and bitway providers:Services and bitway providers:–– Administration and economies of scaleAdministration and economies of scale
■■ Independent application developerIndependent application developer–– Economically significant market built on existing Economically significant market built on existing
infrastructureinfrastructure
■■ UserUser–– Multimedia applicationsMultimedia applications
–– Diversity of applicationsDiversity of applications
–– Single services and bitway access providerSingle services and bitway access provider
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The open horizontal interfaceThe open horizontal interface
Services
Bitways
ApplicationsOperating system & telephone API
Internet protocol (IP) & QoS
Async. transfer mode (ATM)
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More layers emergingMore layers emerging
Middleware services
Network services
Bitways
Applications
Application components E.g. OpenDoc, ActiveX
E.g. CORBA
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Information appliancesInformation appliances
Captures a turnkey stovepipe application snapshot in one “easy-to-use” product
e.g. WebTV, Nokia Comunicator
Middleware services
Network services
Bitways
Applications
Application components
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Obstacles to innovationObstacles to innovation
All users possessing the clientapplication immediately benefit fully
Users possessing the peerapplication benefit only to the
extent that there are other peerswith an interoperable application
Client-server
Peer-to-peer
Networkexternality
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Transportable computationTransportable computation
■■ Transport not only data, but also Transport not only data, but also computation across the networkcomputation across the network
■■ Primary impacts:Primary impacts:–– ScalabilityScalability
–– InteroperabilityInteroperability
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Network distributionNetwork distribution
Client ServerNetwork
ClientapplicationrepositorySlow distribution is replaced by
distribution of the client application over the network itself
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Virtual machine interfaceVirtual machine interface
Virtual machine
Operating system
Applications
Java bytecode interpreterTelescript
UNIX, MacOS, Win95
WWW browser
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Dynamic deployment: client-serverDynamic deployment: client-server
Client Server
Clientapplet
repositoryFunctionality is invoked during asession by dynamically distributingexecutable code during the session itself
Network
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Applet executionApplet execution
Source code
Compiler
Dynamic
deployment Client
Languages: Tcl Telescript Java
PC, Mac, PDA,telephone, etc
Bytecode virtualmachine
ClientStored on server
Platform-independentbytecode
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Example Java appletExample Java applet
Nuclearreactor simulation
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AdvantagesAdvantages
■■ Client-server:Client-server:–– No functional advantage over, say XNo functional advantage over, say X
–– Reduced latencyReduced latency
–– ScalabilityScalability
■■ Peer-to-peerPeer-to-peer–– Bypasses network externalityBypasses network externality
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Dynamic deployment: peer-to-peerDynamic deployment: peer-to-peer
Peer PeerNetwork
Peer appletrepositoryNetwork externality problem is
avoided by deploying the peer application during establishment, or dynamically during the session
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Java-to-ShareJava-to-Share
■■ Helper application for standard Java-Helper application for standard Java-enabled WWW browserenabled WWW browser
■■ Turns client-server WWW browser into Turns client-server WWW browser into platform for user-to-user applications in platform for user-to-user applications in peer-to-peer architecturepeer-to-peer architecture
■■ Peers need not have application software in Peers need not have application software in advanceadvance
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Java-to-ShareJava-to-Share
Netscapebrowser
Netscapebrowser
Javavirtual
machine
Javavirtual
machine
Javaapplet Http
server
Java applets
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Endpoint: complete convergenceEndpoint: complete convergence
Client/peer
Repository
Client/peer
Repository
Client/peer
RepositoryServer
Repository
Server
Repository
Collaborationcontext
Informationcontext