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Web%20Services%20and%20Grid%20Architecture%20and%20their%20application%20to%20Earthquake%20Science

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Information in systems varies from coherent (harmonious) to incoherent limits ... Can consider N plus N Grids as Coherent or Harmonious Grids. I = (NM)0.5. ... – PowerPoint PPT presentation

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Title: Web%20Services%20and%20Grid%20Architecture%20and%20their%20application%20to%20Earthquake%20Science


1
Web Services and Grid Architecture and their
application to Earthquake Science
  • USC AIST Meeting
  • August 31 2004
  • Geoffrey Fox
  • Community Grids Lab
  • Indiana University
  • gcf_at_indiana.edu

2
Philosophy of Web Service Grids
  • Much of Distributed Computing was built by
    natural extensions of computing models developed
    for sequential machines
  • This leads to the distributed object (DO) model
    represented by Java and CORBA
  • RPC (Remote Procedure Call) or RMI (Remote Method
    Invocation) for Java
  • Key people think this is not a good idea as it
    scales badly and ties distributed entities
    together too tightly
  • Distributed Objects Replaced by Services
  • Note CORBA was considered too complicated in both
    organization and proposed infrastructure
  • and Java was considered as tightly coupled to
    Sun
  • So there were other reasons to discard
  • Thus replace distributed objects by services
    connected by one-way messages and not by
    request-response messages

3
Web services
  • Web Services build loosely-coupled, distributed
    applications, based on the SOA principles.
  • Web Services interact by exchanging messages in
    SOAP format
  • The contracts for the message exchanges that
    implement those interactions are described via
    WSDL interfaces.

4
What is a Grid?
  • You wont find a clear description of what is
    Grid and how does differ from a collection of Web
    Services
  • I see no essential reason that Grid Services have
    different requirements than Web Services
  • Geoffrey Fox, David Walker, e-Science Gap
    Analysis, June 30 2003. Report UKeS-2003-01,
    http//www.nesc.ac.uk/technical_papers/UKeS-2003-0
    1/index.html.
  • Notice service-building model is like
    programming language very personal!
  • Grids were once defined as Internet Scale
    Distributed Computing but this isnt good as
    Grids depend as much if not more on data as well
    as simulations
  • So Grids can be termed Internet Scale
    Distributed Services and represent a way of
    collecting services together to solve problems
    where special features and quality of service
    needed.

5
e-Infrastructure
  • e-Infrastructure builds on the inevitable
    increasing performance of networks and computers
    linking them together to support new flexible
    linkages between computers, data systems and
    people
  • Grids and peer-to-peer networks are the
    technologies that build e-Infrastructure
  • e-Infrastructure called CyberInfrastructure in
    USA
  • We imagine a sea of conventional local or global
    connections supported by the ordinary Internet
  • Phones, web page accesses, plane trips, hallway
    conversations
  • Conventional Internet technology manages billions
    of broadcast or low (one client to Server) or
    broadcast links
  • On this we superimpose high value multi-way
    organizations (linkages) supported by Grids with
    optimized resources and system support
  • Low multiplicity fully interactive real-time
    sessions
  • Resources such as databases supporting (larger)
    communities

6
N plus N Community Resources
  • Grid Community databases have analogy to
    Television and the News Web that allow
    individuals to communicate instantly with each
    other via Web Pages and Headline News acting as
    proxies
  • N resources deposit information and N can view ?
    Call N plus N

7
Large and Small Grids
  • N resources in a community (N is billions for the
    world and 1000-10000 for many scientific fields)
  • Communities are arranged hierarchically with real
    work being done in groups of M resources M
    could be 10-100 in e-Science
  • Metcalfes law value of network grows like
    square of number of nodes M we call Grids where
    this true Metcalfe or M2 Grids
  • Nature of Interaction depends on size of M or N
  • N plus N Shared Information Grids for largish N
  • M2 Metcalfe Grids for smaller M lt N
  • Technology support depends on M/N might use a
    relatively static DHT (Distributed Hash Table)
    for large N and a distributed shared memory for
    small M
  • Grids must merge with peer-to-peer networks to
    support both N plus N and M2 Systems

8
M2 Interactions
  • Superimpose M way Grids on the sea (heatbath)
    of 2 by N or N plus N ordinary interactions

Grids also support many community N plus N
resources
Implement Grids as a software overlay network
9
Information Complexity I
  • Consider a community of N resources with groups
    of size M with each group complexity C
  • N/M Groups
  • Information in systems varies from coherent
    (harmonious) to incoherent limits
  • Web and Grid data resources supply coherence as
    in curated astronomy, bioinformatics, geophysics
    database
  • Can consider N plus N Grids as Coherent or
    Harmonious Grids
  • I (NM)0.5 . (C/M) Incoherent to N . (C/M)
    Coherent
  • In this language Grids do one or both of
  • Coherence/Harmony common shared asynchronous
    resources
  • Interactivity Increase complexity to M2 with
    real-time linkage of interacting resources

10
Information Complexity II
  • N plus N Community database has I N Coherent
  • Improving on N0.5 incoherent case
  • Nearest Neighbor groups is I (NM)0.5
  • Becoming I N in limit M N
  • M is correlation length in Complex Systems
    approach
  • M-ary Interactive group (M2 Metcalfe Grids) has C
    M2 and I (NM3)0.5 Incoherent to I
    NM Coherent
  • Coherent case most natural in science due to
    synergy between Metcalfe and Coherence Grids
  • Small World (logarithmic) networks and
    hierarchical group structure require more
    discussion

11
Architecture of (Web Service) Grids
  • Grids built from Web Services communicating
    through an overlay network built in SOFTWARE on
    the ordinary internet at the application level
  • Grids provide the special quality of service
    (security, performance, fault-tolerance) and
    customized services needed for distributed
    complex enterprises
  • We need to work with Web Service community as
    they debate the 60 or so proposed Web Service
    specifications
  • Use Web Service Interoperability WS-I as best
    practice
  • Must add further specifications to support high
    performance
  • Database Grid Services for N plus N case
  • Streaming support for M2 case

12
Importance of SOAP
  • SOAP defines a very obvious message structure
    with a header and a body
  • The header contains information used by the
    Internet operating system
  • Destination, Source, Routing, Context, Sequence
    Number
  • The message body is only used by the application
    and will never be looked at by operating system
    except to encrypt, compress it etc.
  • Much discussion in field revolves around what is
    in header!
  • e.g. WSRF adds a lot to header

13
Web Services
  • Java is very powerful partly due to its many
    frameworks that generalize libraries e.g.
  • Java Media Framework
  • Java Database Connectivity JDBC
  • Web Services have a correspondingly collections
    of specifications that represent critical
    features of the distributed operating systems for
    Grids of Simple Services
  • Some 60 active WS- specifications for areas such
    as
  • a. Core Infrastructure Specifications
  • b. Service Discovery
  • c. Security
  • d. Messaging
  • e. Notification
  • f. Workflow and Coordination
  • g. Characteristics
  • h. Metadata and State
  • i. User Interfaces

14
A List of Web Services I
  • a) Core Service Architecture
  • XSD XML Schema (W3C Recommendation) V1.0 February
    1998, V1.1 February 2004
  • WSDL 1.1 Web Services Description Language
    Version 1.1, (W3C note) March 2001
  • WSDL 2.0 Web Services Description Language
    Version 2.0, (W3C under development) March 2004
  • SOAP 1.1 (W3C Note) V1.1 Note May 2000
  • SOAP 1.2 (W3C Recommendation) June 24 2003
  • b) Service Discovery
  • UDDI (Broadly Supported OASIS Standard) V3 August
    2003
  • WS-Discovery Web services Dynamic Discovery
    (Microsoft, BEA, Intel ) February 2004
  • WS-IL Web Services Inspection Language, (IBM,
    Microsoft) November 2001

15
A List of Web Services II
  • c) Security
  • SAML Security Assertion Markup Language (OASIS)
    V1.1 May 2004
  • XACML eXtensible Access Control Markup Language
    (OASIS) V1.0 February 2003
  • WS-Security 2004 Web Services Security SOAP
    Message Security (OASIS) Standard March 2004
  • WS-SecurityPolicy Web Services Security Policy
    (IBM, Microsoft, RSA, Verisign) Draft December
    2002
  • WS-Trust Web Services Trust Language (BEA, IBM,
    Microsoft, RSA, Verisign ) May 2004
  • WS-SecureConversation Web Services Secure
    Conversation Language (BEA, IBM, Microsoft, RSA,
    Verisign ) May 2004
  • WS-Federation Web Services Federation Language
    (BEA, IBM, Microsoft, RSA, Verisign) July 2003

16
A List of Web Services III
  • d) Messaging
  • WS-Addressing Web Services Addressing (BEA, IBM,
    Microsoft) March 2004
  • WS-MessageDelivery Web Services Message Delivery
    (W3C Submission by Oracle, Sun ..) April 2004
  • WS-Routing Web Services Routing Protocol
    (Microsoft) October 2001
  • WS-RM Web Services Reliable Messaging (BEA, IBM,
    Microsoft, Tibco) v0.992 March 2004
  • WS-Reliability Web Services Reliable Messaging
    (OASIS Web Services Reliable Messaging TC) March
    2004
  • SOAP MOTM SOAP Message Transmission Optimization
    Mechanism (W3C) June 2004
  • e) Notification
  • WS-Eventing Web Services Eventing (BEA,
    Microsoft, TIBCO) January 2004
  • WS-Notification Framework for Web Services
    Notification with WS-Topics, WS-BaseNotification,
    and WS-BrokeredNotification (OASIS) OASIS Web
    Services Notification TC Set up March 2004
  • JMS Java Message Service V1.1 March 2002

17
A List of Web Services IV
  • f) Coordination and Workflow, Transactions and
    Contextualization
  • WS-CAF Web Services Composite Application
    Framework including WS-CTX, WS-CF and WS-TXM
    below (OASIS Web Services Composite Application
    Framework TC) July 2003
  • WS-CTX Web Services Context (OASIS Web Services
    Composite Application Framework TC) V1.0 July
    2003
  • WS-CF Web Services Coordination Framework (OASIS
    Web Services Composite Application Framework TC)
    V1.0 July 2003
  • WS-TXM Web Services Transaction Management (OASIS
    Web Services Composite Application Framework TC)
    V1.0 July 2003
  • WS-Coordination Web Services Coordination (BEA,
    IBM, Microsoft) September 2003
  • WS-AtomicTransaction Web Services Atomic
    Transaction (BEA, IBM, Microsoft) September 2003
  • WS-BusinessActivity Web Services Business
    Activity Framework (BEA, IBM, Microsoft) January
    2004
  • BTP Business Transaction Protocol (OASIS) May
    2002 with V1.0.9.1 May 2004
  • BPEL Business Process Execution Language for Web
    Services (OASIS) V1.1 May 2003
  • WS-Choreography (W3C) V1.0 Working Draft April
    2004
  • WSCI (W3C) Web Service Choreography Interface
    V1.0 (W3C Note from BEA, Intalio, SAP, Sun,
    Yahoo)
  • WSCL Web Services Conversation Language (W3C
    Note) HP March 2002

18
A List of Web Services V
  • h) Metadata and State
  • RDF Resource Description Framework (W3C) Set of
    recommendations expanded from original February
    1999 standard
  • DAMLOIL combining DAML (Darpa Agent Markup
    Language) and OIL (Ontology Inference Layer)
    (W3C) Note December 2001
  • OWL Web Ontology Language (W3C) Recommendation
    February 2004
  • WS-DistributedManagement Web Services Distributed
    Management Framework with MUWS and MOWS below
    (OASIS)
  • WSDM-MUWS Web Services Distributed Management
    Management Using Web Services (OASIS) V0.5
    Committee Draft April 2004
  • WSDM-MOWS Web Services Distributed Management
    Management of Web Services (OASIS) V0.5 Committee
    Draft April 2004
  • WS-MetadataExchange Web Services Metadata
    Exchange (BEA,IBM, Microsoft, SAP) March 2004
  • WS-RF Web Services Resource Framework including
    WS-ResourceProperties, WS-ResourceLifetime,
    WS-RenewableReferences, WS-ServiceGroup, and
    WS-BaseFaults (OASIS) Oasis TC set up April 2004
    and V1.1 Framework March 2004
  • ASAP Asynchronous Service Access Protocol (OASIS)
    with V1.0 working draft G June 2004
  • WS-GAF Web Service Grid Application Framework
    (Arjuna, Newcastle University) August 2003

19
A List of Web Services VI
  • g) General Service Characteristics
  • WS-Policy Web Services Policy Framework (BEA,
    IBM, Microsoft, SAP) May 2003
  • WS-PolicyAssertions Web Services Policy
    Assertions Language (BEA, IBM, Microsoft, SAP)
    May 2003
  • WS-Agreement Web Services Agreement Specification
    (GGF under development) May 2004
  • i) User Interfaces
  • WSRP Web Services for Remote Portlets (OASIS)
    OASIS Standard August 2003
  • JSR168 JSR-000168 Portlet Specification for Java
    binding (Java Community Process) October 2003

20
WS-I Interoperability
  • Critical underpinning of Grids and Web Services
    is the gradually growing set of specifications in
    the Web Service Interoperability Profiles
  • Web Services Interoperability (WS-I)
    Interoperability Profile 1.0a."
    http//www.ws-i.org. gives us XSD, WSDL1.1,
    SOAP1.1, UDDI in basic profile and parts of
    WS-Security in their first security profile.
  • We imagine the 60 Specifications being checked
    out and evolved in the cauldron of the real world
    and occasionally best practice identifies a new
    specification to be added to WS-I which gradually
    increases in scope
  • Note only 4.5 out of 60 specifications have made
    it in this definition

21
Web Services Grids and WS-I
  • WS-I Interoperability doesnt cover all the
    capabilities need to support Grids
  • WS-I is designed to minimal extension of WS-I to
    support most current Grids it adds support for
  • Enhanced SOAP Addressing (WS-Addressing)
  • Fault tolerant (reliable) messaging
  • Workflow as in IBM-Microsoft standard BPEL
  • Security and Notification best practice and
    support will probably get added soon
  • There are Web Service frameworks here but various
    IBM v Microsoft v Globus differences to be
    resolved
  • Portlet-based User Interfaces could be added
  • UK OMII Open Middleware Infrastructure Institute
    is adopting this approach to support UK e-Science
    program
  • Currently UK e-Science largely either uses GT2
    (as in EDG) or Simple Web Services for database
    Grids
  • http//www.omii.ac.uk/

22
Application Specific Grids Generally Useful
Services and Grids Workflow WSFL/BPEL Service
Management (Context etc.) Service Discovery
(UDDI) / Information Service Internet Transport ?
Protocol Service Interfaces WSDL
Higher Level Services
Service Context
Service Internet
Base Hosting Environment
Protocol HTTP FTP DNS Presentation XDR
Session SSH Transport TCP UDP Network IP
Data Link / Physical
Bit level Internet (OSI Stack)
Layered Architecture for Web Services and Grids
23
How SERVOGrid Fits In
  • There is core Web Services the operating
    system of the world controlled by WS-
  • There is workflow programming the Grid
  • There are very general Web Services and Grids
    such as
  • Database
  • Collaboration
  • Job Submittal
  • There are some relatively general services and
    Grids such as
  • Visualization
  • GIS
  • There are application specific services such as
  • Virtual California

24
Layers of Onion
Application (level 1 Programming)
Application Semantics (Metadata, Ontology) Level
2 Programming
Systems Metadata (Context, State)
Basic WS- Infrastructure
Web Service 1
WS 2
WS 3
WS 4
Workflow (level 3) Programming
All SERVOGrid capabilities are built as Web
Services with this structure 3 level programming
model
25
Working up from the Bottom
  • We have the classic (CISCO, Juniper .) Internet
    routing the flood of ordinary packets in OSI
    stack architecture
  • Web Services build the Service Internet or IOI
    (Internet on Internet) with
  • Routing via WS-Addressing not IP header
  • Fault Tolerance (WS-RM not TCP)
  • Security (WS-Security/SecureConversation not
    IPSec/SSL)
  • Information Services (UDDI/WS-Context not
    DNS/Configuration files)
  • At message/web service level and not packet/IP
    address level
  • Software-based Service Internet possible as
    computers fast
  • Familiar from Peer-to-peer networks and built as
    a software overlay network defining Grid (analogy
    is VPN)
  • SOAP Header contains all information needed for
    the Service Internet (Grid Operating System)
    with SOAP Body containing information for Grid
    application service

26
Consequences of Rule of the Millisecond
  • Useful to remember critical time scales
  • 1) 0.000001 ms CPU does a calculation
  • 2) 0.001 to 0.01 ms MPI latency
  • 3) 1 to 10 ms wake-up a thread or
    process
  • 4) 10 to 1000 ms Internet delay
  • 4) implies geographically distributed
    metacomputing cant in general compete with
    parallel systems (OK for some cases)
  • 3) ltlt 4) implies RPC not a critical programming
    abstraction as it ties distributed entities
    together and gains a time that is typically only
    1 of inevitable network delay
  • However many service interactions are at their
    heart RPC but implemented differently at times
    e.g. asynchronously
  • 2) says MPI is not relevant for a distributed
    environment as low latency cannot be exploited
  • Even more serious than using RMI/RPC, current
    Object paradigms also lead to mixed up services
    with unclear boundaries and autonomy
  • Web Services are only interesting model for
    services today

27
Linking Modules
  • From method based to RPC to message based to
    event-based

Listener Subscribe to Events
Publisher Post Events
Message Queue in the Sky
28
What is a Simple Service?
  • Take any system it has multiple functionalities
  • We can implement each functionality as an
    independent distributed service
  • Or we can bundle multiple functionalities in a
    single service
  • Whether functionality is an independent service
    or one of many method calls into a glob of
    software, we can always make them as Web
    services by converting interface to WSDL
  • Simple services are gotten by taking
    functionalities and making as small as possible
    subject to rule of millisecond
  • Distributed services incur messaging overhead of
    one (local) to 100s (far apart) of milliseconds
    to use message rather than method call
  • Use scripting or compiled integration of
    functionalities ONLY when require lt1 millisecond
    interaction latency
  • Apache web site has many projects that are
    multiple functionalities presented as (Java)
    globs and NOT (Java) Simple Services
  • Makes it hard to integrate sharing common
    security, user profile, file access .. services

29
Grids of Grids of Simple Services
  • Link via methods ? messages ? streams
  • Services and Grids are linked by messages
  • Internally to service, functionalities are linked
    by methods
  • A simple service is the smallest Grid
  • We are familiar with method-linked
    hierarchy Lines of Code ? Methods ? Objects ?
    Programs ? Packages

30
Component Grids?
  • So we build collections of Web Services which we
    package as component Grids
  • Visualization Grid
  • Sensor Grid
  • Utility Computing Grid
  • Person (Community) Grid
  • Earthquake Simulation Grid
  • Control Room Grid
  • Crisis Management Grid
  • We build bigger Grids by composing component
    Grids using the Service Internet

31
Critical Infrastructure (CI) Grids built as Grids
of Grids
32
Repositories Federated Databases
Streaming Data
Sensors
Database
Database
Sensor Grid
Database Grid
Research
Education
SERVOGrid
Compute Grid
Customization Services From Research to Education
Data Filter Services
Research Simulations
Analysis and Visualization Portal
Education Grid Computer Farm
Geoscience Research and Education Grids
33
IOI and CIE
  • Let us study the two layers IOI (Service Internet
    On the Bit Internet) and CIE (Context and
    Information Environment)
  • IOI is most straightforward as it is providing
    reasonably well understood capabilities at a new
    level
  • CIE is roughly the inter-service shared memory
    used to manage and control them at distributed
    operating system level
  • Critical is shared (a database service) versus
    message based CIE

Higher Level Services
Application Specific Grids Generally Useful
Services and Grids Workflow WSFL/BPEL Service
Management (Context etc.) Service Discovery
(UDDI) / Information Service Internet Transport ?
Protocol Service Interfaces WSDL
CIE
IOI
34
NaradaBrokering
Web Service B
Queues
Stream
Server-enhanced Messaging
NB supports messages and streams
35
NaradaBrokering and IOI
  • Software Overlay Network features
  • Support for Multiple Transport protocols
  • Support for multiple delivery mechanisms
  • Reliable Delivery
  • Exactly-once Delivery
  • Ordered Delivery
  • Optional Delivery optimization modules for
    different modes
  • Compression/Decompression of payloads with
    optional module
  • Coalescing/Fragmentation of payloads with
    optional module
  • NTP Time Service
  • Security Service
  • Performance Monitoring
  • Performance optimized routing with optional
    module
  • Support for WS-Reliability, WS-ReliableMessaging
    and their Federation

36
Virtualizing Communication
  • Communication specified in terms of user goal and
    Quality of Service not in choice of port number
    and protocol
  • Bit Internet Protocols have become overloaded
    e.g. MUST use UDP for A/V latency requirements
    but CANt use UDP as firewall will not support
  • A given Service Internet communication can
    involve multiple transport protocols and multiple
    destinations the latter possibly determined
    dynamically

NB Brokers
Fast Link
Firewall HTTP
B1
Satellite UDP
A
Hand-Held Protocol
B2
Software Multicast
Dial-up Filter
B3
NB Broker
Client Filtering
37
Performance Monitoring
  • Every broker incorporates a Monitoring service
    that monitors links originating from the node.
  • Every link measures and exposes a set of metrics
  • Average delays, jitters, loss rates, throughput.
  • Individual links can disable measurements for
    individual or the entire set of metrics.
  • Measurement intervals can also be varied
  • Monitoring Service, returns measured metrics to
    Performance Aggregator.

38
NaradaBrokering Service Integration
Proxy Messaging
Handler Messaging
Notification
Internal to Service SOAP Handlers/Extensions/Plug
-ins Java (JAX-RPC) .NET Indigo and special
cases PDA's  gSOAP, Axis C
39
Fast Web Service Communication I
  • IOI Application level Internet allows one to
    optimize message streams at the cost of startup
    time, Web Services can deliver the fastest
    possible interconnections with or without
    reliable messaging
  • Typical results from Grossman (UIC) comparing
    Slow SOAP over TCP with binary and UDP transport
    (latter gains a factor of 1000)

7020
5.60
40
Fast Web Service Communication II
  • Mechanism only works for streams sets of
    related messages
  • SOAP header in streams is constant except for
    sequence number (Message ID), time-stamp ..
  • One needs two types of new Web Service
    Specification
  • WS-StreamNegotiation to define how one can use
    WS-Policy to send messages at start of a stream
    to define the methodology for treating remaining
    messages in stream
  • WS-FlexibleRepresentation to define new
    encodings of messages

41
Fast Web Service Communication III
  • Then use WS-StreamNegotiation to negotiate
    stream in Tortoise SOAP ASCII XML over HTTP and
    TCP
  • Deposit basic SOAP header through connection it
    is part of context for stream (linking of 2
    services)
  • Agree on firewall penetration, reliability
    mechanism, binary representation and fast
    transport protocol
  • Naturally transport UDP plus WS-RM
  • Use WS-FlexibleRepresentation to define
    encoding of a Fast transport (On a different
    port) with messages just having
    FlexibleRepresentationContextToken, Sequence
    Number, Time stamp if needed
  • RTP packets have essentially this structure
  • Could add stream termination status
  • Can monitor and control with original negotiation
    stream
  • Can generate different streams optimized for
    different end-points

42
CIE Common Service Information and Metadata
  • Consider a collection of services working
    together
  • Workflow tells you how to specify service
    interaction but more basically there is shared
    information or context specifying/controlling
    collection
  • WS-RF and WS-GAF have different approaches to
    contextualization supplying a common context
    which at its simplest is a token to represent
    state
  • More generally core shared information includes
    dynamic service metadata and the equivalent of
    configuration information.
  • One can supports such a common context either as
    pool of messages or as message-based access to a
    database (Context Service)
  • Two services linked by a stream are perhaps
    simplest example of a collection of services
    needing context
  • Note that there is a tension between storing
    metadata in messages and services.
  • This is shared versus distributed memory debate
    in parallel computing

43
Four Metadata Architectures
System or Federated Registry or Metadata Catalog
Grid or Domain Specific Metadata Catalogs
Web Service Ports
Individual Services
Messages
44
Notification Architecture
  • Point-to-Point
  • Or Brokered
  • NaradaBrokering will support both WS-Eventing and
    WS-Notification as well as Java Message Service
    JMS that is Java Notification standard

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45
Architecture Characteristics
  • Build as Component Web Services Grids
  • Simulation
  • Visualization
  • GIS
  • Database
  • NaradaBrokering provides
  • Fault Tolerance
  • Support for High Performance Streams
  • Basic Dynamic Information Environment
  • Notification
  • HPSearch provides
  • More flexible information environment with
    scripting
  • Can prototype simple workflow before implementing
    in BPEL
  • Scripted Information Environment plus Workflow
    supports Complexity (multi-scale iterations)
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