Tuesday, March 22, 2011

Service-oriented architecture(SOA)


SOA:- 
It is an IT Strategy that organizes the discrete functions contained in enterprise applications into inter-operable standards based services that can be combined and reused quickly to meet business requirement. In simple words, we can say SOA is the integration of web services for implementing business logic.
Or more precisely, we can say "SOA is a strategy for developing and integrating systems through interoperable standards-based services."
Benefits:-                                           
· Reusability: Existing business functionality in an application can be reused to meet new business requirements. A business process is decomposed into discrete reusable functional components.
· Interoperability: Communication between services and the business process is not dependent on the platform and are standards enabled. The services are also not tightly coupled to the application. A consumer of service is decoupled from service provider.
· Scalability: Applications are flexible to the changing business requirements.
· Cost Efficiency: This is highly cost efficient as integrating the business resources is standards based.

Services:-
Services are the building blocks of SOA enabled application. It is basically an encapsulation of data and business logic. A service consists of an interface, has an implementation and exhibits certain pre-defined behavior.
The service interface defines a set of operations, which portrays (or exposes) its capabilities. Operations are the things that a service can do.

Standards Used by SOA Suite:-
· Services Component Architecture (SCA) assembly model:-
SCA specifications provide a programming model for building applications and systems based on an SOA approach.
SOA is a set of standards or strategies and SCA is an implementation of those standards or strategies.

· Service Data Object (SDO):-
An SDO is designed to simplify and unify the way in which applications handle data. An SDO exposes any data source as a service, which enables retrieval and manipulation of the data in an XML format through service operations. Using SDO, application programmers can uniformly access and manipulate data from heterogeneous data sources, including relational databases, XML data sources, Web services, and enterprise information systems. The task of connecting applications to data sources is performed by a data mediator service. SDO enables both a static (or strongly typed) programming model and a dynamic (or loosely typed) programming model.
· Business Process Execution Language (BPEL):-
It provides enterprises with an industry standard to orchestrate and execute business process. Using BPEL, we design a business process that integrates a series of discrete services into an end-to-end process flow.
· XSL Transformation (XSLT):-
It is a transformation language that helps in transforming one XML schema to another.
· Java Connector Architecture (JCA):-
It provides a java tech. solution to the problem of connectivity between many application servers in Enterprise Information System (EIS).
· Web Services Definition Language (WSDL):-
It provides all the description of a service for e.g. How to access the service, what all operations a service can perform, what are the inputs to the service and what output service is going to provide etc.
· Simple Object Access Protocol (SOAP):-
Exchange of data takes place using messages. These messages are defined and delivered using a network protocol that is known as SOAP.
· XML Schema Definition (XSD):-
It provides the definition of the xml that is used as input or output for a service. It defines all the elements that are there in an input or output file.

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    Saturday, February 5, 2011

    IPv6 marks the next chapter in the history of the Internet

    In the same way your phone is associated with a unique number, your computer is assigned a unique Internet Protocol (IP) address when you connect to the Internet. The current protocol, IPv4, allows for approximately 4 billion unique addresses—and that number is about to run out.

    This morning the Internet Corporation for Assigned Names and Numbers (ICANN) announced (PDF) that it has distributed the last batch of its remaining IPv4 addresses to the world’s five Regional Internet Registries, the organizations that manage IP addresses in different regions. These Registries will begin assigning the final IPv4 addresses within their regions until they run out completely, which could come as soon as early 2012.

    As the last blocks of IPv4 addresses are assigned, adoption of a new protocol—IPv6—is essential to the continued growth of the open Internet. IPv6 will expand Internet address space to 128 bits, making room for approximately 340 trillion trillion trillion addresses (enough to last us for the foreseeable future).

    Google, along with others, has been working for years to implement the larger IPv6 format. We’re also participating in the planned World IPv6 Day, scheduled for June 8, 2011. On this day, all of the participating organizations will enable access to as many services as possible via IPv6.

    Today’s ICANN announcement marks a major milestone in the history of the Internet. IPv6, the next chapter, is now under way.