Enterprise Application Integration (EAI) is the integration 
of new application software such as middleware tools with 
existing software which provides the functionality that 
supports the enterprise’s business processes. 

A framework which allows rapid development and Reuse of 
interfaces among Disparate enterprise systems by achieving 
isolation of business logic and improved administrative 
control.

There are basically two architecture HUB & SPOKE/BUS. Based 
on that various integration tools are vailable in the 
martket. Few of them are-

1) Hub & Spoke architecture- WebMethods – Integration 
Platform, Vitria Technology – BusinessWare, WBI – 
Collaborators, Connectors  
2) Bus architecture- Tibco Active Enterprise , SeeBeyond 
eGATE Integrator