Communication Paradigms

INF 5040 autumn 2010

lecturer: Roman Vitenberg

INF5040, Roman Vitenberg

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What is a communication paradigm?
It is a set of communication primitives  Network adapters allow us to send data using MAClayer primitives  Transport layer endows us with sockets  How could we raise the abstraction further?


Study of a communication paradigm:  Properties  Target applications  Underlying implementation concepts INF5040, Roman Vitenberg

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Communication properties
Addressing scheme and space decoupling  Underlying protocol addresses (IP) – no decoupling  Logical aliases – partial decoupling – DNS and NAT translation, service names, email aliases

 Content-based addressing – full decoupling – Interactions are declarative


Persistence level  Fully persistent  Fully transient  Intermediate INF5040, Roman Vitenberg

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Communication properties
Synchrony  Fully synchronous  Fully asynchronous  Intermediate

sender app

receiver app

middleware & os

– middleware-level sync – man-in-the-middle – others

middleware & os

network media


Time decoupling INF5040, Roman Vitenberg

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(some)

Communication paradigms


Remote procedure call  Object-based (CORBA, Java RMI, DCOM)  Earlier data-based (DCE, Sun RPC)


Message-oriented communication
Stream-oriented communication
Software-based distributed shared memory (DSM) INF5040, Roman Vitenberg

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Message-oriented communication paradigms

(some)


Raw socket programming
Message-passing interface (MPI)
Message-oriented middleware (MOM)
Publish-subscribe communication

INF5040, Roman Vitenberg

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Raw socket programming
Addressing scheme: IP addresses
No time decoupling
Transient
Mainly used for building higher-level abstractions

INF5040, Roman Vitenberg

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Message-programming interface (MPI)
Addressing scheme  A group of nodes assigned logical addresses


Failures are considered fatal
Transient without time decoupling
Data-oriented (advanced data manipulation)  Basic API: MPI_send, MPI_recv  Data-oriented API: MPI_scatter,MPI_gather


Use: parallel computation in fast networks INF5040, Roman Vitenberg

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Message-oriented middleware (MOM)
Addressing scheme: logical queue name
Persistent
Full time decoupling put(msg,dest queue name) Sender Queuing layer OS layer

get(local queue name) Receiver Queuing layer OS layer

INF5040, Roman Vitenberg

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Routing in MOM
Handles queue name to address translation  Hierarchical names: {queue manager, internal id}


Message brokers perform inter-domain routing with format conversion Sender Queuing layer OS layer

Message broker

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Receiver Queuing layer OS layer

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MOM applications & implementations
Implementations: IBM MQ, Oracle AQ
The E-mail application
Workflow and other collaborative apps
Federated information systems Query

DB 1

DB 3

DB 2 INF5040, Roman Vitenberg

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Publish-subscribe communication subscribers

publishers

Pub-sub service IBM: -3,75

S1: “IBM” & v