To make it simple, just visualize that a JVM is a node agent, an application server or a deployment manager. Each Core Group has only one logical High Availability Manager, and that HA Manager services all the members of the Core Group. The HA Manager is responsible for making the various services within a Core Group highly available and scalable.

Conclusion
WebSphere Extended Deployment extends the J2EE environment with mainframe-class application platform capabilities building on what IBM has learned in high transactional custom development on J2EE. With WebSphere Extended Deployment, IBM brings some of this capability to other platforms including Linux/Intel, AIX, Solaris, and Windows. While competitor offerings can provide scalability for high-end transactional environments, none offer virtualization and partitioning flexibility, which in turn increases hardware utilization efficiency.

Kadhar Masthan is an e-business technical architect in Cognizant Technology Solutions, a major IT solutions provider and a business partner of IBM. His areas of expertise include Web applications and infrastructure development using WebSphere, DB2, WebSphere MQ and Tivoli. He extensively takes training and writes articles about WebSphere architecture. Till now, Kadhar co-authored 5 Redbooks for IBM on WebSphere and Tivoli architecture. Kadhar can be reached at kadhar@chn.cognizant.com.