Explain Service-Oriented Architecture (SOA) with its layered architecture, tools, evolution, and comparison between Grids and Clouds

Explain Service-Oriented Architecture (SOA) with its layered architecture, tools, evolution, and comparison between Grids and Clouds

Answer:-

Service-Oriented Architecture (SOA) is a method of designing and building software systems using services. Each service performs a specific task and communicates with other services over a network.

Layered Architecture of SOA

• SOA is built on OSI layers, and on top of that, it uses software like .NET, Apache Axis, or Java Virtual Machine.
• Communication happens using tools like:
  • WSDL for Web Services
  • RMI for Java
  • IDL/IIOP for CORBA
• Common communication protocols: SOAP, HTTP, TCP/IP, JMS, etc.
• Middleware like WebSphere MQ handles routing, messaging, and fault recovery.
• Security is managed using standards like IPSec, SSL, etc.
• Registry and discovery services: JNDI, UDDI, LDAP, ebXML
• Management services handle the lifetime and state of services.

Tools Used in SOA

There are two popular approaches:

1. Web Services (SOAP-based):
   • Uses SOAP messages to send/receive data.
   • Fully specifies all parts of a service.
   • Example tool: Apache Axis.
2. RESTful Services:
   • Simpler, lightweight, and uses HTTP + XML/JSON.
   • Header is minimal; most data is in the message body.
   • Faster and better for fast-changing environments.

Evolution of SOA

• Early systems used Java and CORBA.
• Modern SOA supports clouds, grids, and even inter-clouds.
• Raw data is collected from sensors (SS) like phones, PCs, or ZigBee.
• Filter Services (fs) clean the data before use.
• Filtered data is passed through:
  • Compute Cloud
  • Storage Cloud
  • Discovery Cloud
• At the end, the processed data reaches a portal used by users.
• Examples of portals: OGFCE, HUBzero.

Grids vs Clouds

• Today, the line between grids and clouds is fading.
• Systems like grid of clouds, cloud of grids, or interclouds are common in SOA.