Transcript Latest techniques and Applications in Interprocess Communication

Latest techniques and
Applications in Interprocess
Communication and Coordination
Xiaoou Zhang
Outline
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What is Interprocess communication
Message oriented communication
 Web Services
 WCF
Inter-Process Communication
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Inter-Process Communication (IPC) is a
set of techniques for the exchange of
data among two or more threads in one
or more processes. Processes may be
running on one or more computers
connected by a network.
Distributed System
Communication [1]
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Remote procedure call
a protocol that allows one application to
execute another application or module
on another computer
Message-oriented communication
Messages exchange between systems
Stream-oriented communication and
multicast communication
Advantages of Using Messaging
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[2]
Cross platform integration: Messages can be
the “universal translator” between various
platforms and languages, allowing each
platform to work with their respective native
data type
Asynchronous communications: both the
sender and receiver can be running flat out
and not be constrained by waiting on each
other
Advantages of Using Messaging
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Remote communication: messages replace
the need for the serializing and deserializing
that occurs when one application makes a
remote call to another application.
End-to-end security: messages can transfer
the complete security context to the
consumer using a combination of headers
and tokens
Web services
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software system designed to support
interoperable machine-to-machine
interaction over a network.
web services are the standards-based
way to realize Service-Oriented
Architecture (SOA)
SOA
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SOA is an example of the composite computing
model
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[3]
The composite computing model is an architecture that uses
distributed, discovery-based execution to expose and
manage a collection of service-oriented software assets.
At the fundamental level, an SOA is a collection of
service on a network that communicate with each
other, the services are loosely coupled, have welldefined interfaces and are reusable. An SOA
therefore has a higher-level view of coarse-grained
application development that uses standard
interfaces to hide the underlying technical complexity
SOA + Internet protocols
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The basic building blocks for using web
services are the SOA and Internet protocols.
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Web services can be represented, advertised,
discovered and communicated within a dynamic
environment.
Web services are based on standards and
standards-based technologies, which ensure that
applications are compliant, thereby enabling
program-to-program interoperability.
Main components
Web services protocol stack is based on
standardized XML technologies. There
are three main components:
 Simple Object Access Protocol (SOAP)
 Web Services Description Language
(WSDL)
 Universal Description, Discovery, and
Integration (UDDI)
SOAP
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[3]
SOAP is a lightweight communication protocol
for web services.
It is used to exchange structured and typed
information between systems.
SOAP allows users to invoke methods on
remote machines without knowing specific
detail of the platform or software running on
those machines.
XML is used to represent the data, while the
data is structured according to the SOAP
schema.
SOAP
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The characteristics of a SOAP message are:
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It is extensible: it allows various features such as
reliability, security, to be layered via SOAP
extensions.
It works across a number of standardized
underlying network protocols.
It is independent of the underlying language or
platform or programming model.
SOAP message
A SOAP message is an ordinary XML document
containing the following elements:
 A required Envelope element that identifies the XML
document as a SOAP message
 An optional Header element that contains header
information
 A required Body element that contains call and
response information
 An optional Fault element that provides information
about errors that occurred while processing the
message
SOAP message example:
the following SOAP message represents a request to transfer
funds between bank accounts:
<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
<soap:Body>
<x:TransferFunds xmlns:x="urn:examples-org:banking">
<from>22-342439</from>
<to>98-283843</to>
<amount>100.00</amount>
</x:TransferFunds>
</soap:Body>
</soap:Envelope>
WSDL
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WSDL is a specification defining how to describe web
services in a common XML grammar. WSDL describes
four critical pieces of data:
 Interface information describing all publicly available
functions
 Data type information for all message requests and
message responses
 Binding information about the transport protocol to
be used
 Address information for locating the specified service
UDDI
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[3]
UDDI is a platform-independent
directory protocol for describing
services and discovering and integrating
services via the Internet. It describes
the details of the services using WSDL
and communicates via SOAP
Implementing Web Services
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A service provider creates a Web service
The service provider uses WSDL to describe the
service to a UDDI registry
The service provider registers the service in a UDDI
registry
Another service or consumer locates and requests
the registered service by querying UDDI.
The requesting service or user writes an application
to bind the registered service using SOAP
Data and messages are exchanged as XML over HTTP
Web services protocols
Window Communication
Foundation (WCF) [2]
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WCF is a programming framework used to
build distributed applications that intercommunicate. WCF is the part of the .NET
Framework dedicated to communications.
Three main design goals of WCF:
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Unification of existing technologies
Interoperability across platform
Service-oriented development
Interoperability across platform
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[4]
WCF’s fundamental communication
mechanism is SOAP-based web services.
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WCF use SOAP messages to interact with
any other application which supports
standard web service.
when a WCF process communicates with
another WCF process, the SOAP messages
can be encoded in an optimized binary
format.
Interoperability across platform
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To allow more than just basic communication, WCF
implements Web services technologies defined by the
WS-* specifications to achieve seamless
Interoperability across platform. Those specifications
covers:
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Messaging: WS-Addressing defines additions to the SOAP
header for addressing SOAP messages, which frees SOAP
from relying on the underlying transport protocol, such as
HTTP, to carry addressing information. Message
Transmission Optimization Mechanism (MTOM) defines an
optimized transmission format for SOAP messages with large
binary data contents based on the XML-binary Optimized
Packaging (XOP) specification.
Interoperability across
platform
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Metadata: WS-Policy allows specification of more dynamic
aspects of a service’s behavior that cannot be expressed in
WSDL, such as a preferred security option. WSMetadataExchange allows a client to directly request
descriptive information about a service, such as its WSDL
and its policies, using SOAP.
Security: WS-Security, WS-SecureConversation, WS-Trust,
and WS-Federation all define additions to SOAP messages
for providing authentication, data integrity, data privacy, and
other security features.
Reliability: WS-Reliable Messaging defines additions to the
SOAP header that allow reliable end-to-end communication,
even when one or more Web services intermediaries must
be traversed.
References
[1] “Distributed Systems: Principles and Paradigms”, Andrew S.
Tanenbaum and Maarten Van Steen, Prentice Hall, 2007
[2] “Pro WCF : practical Microsoft SOA implementation”, Chris Peiris,
Springer, 2007
[3]“From P2P TO Web Services and Grids”, Ian J. Taylor, Springer,
2005
[4]What is Windows Communication Foundation?,
http://msdn.microsoft.com/en-us/library/ms731082.aspx