Oracle agreed on Monday to for US$7.4 billion. After the deal closes, the real work of the companies will follow, including rationalizing a laundry list of identity software.

Both Sun and Oracle for years have been acquiring identity companies, integrating software and developing products to move themselves up the ranks in such identity management areas as access management, provisioning, directories, identity administration and federation.

The two are listed among the Top 5 identity management vendors as judged by consulting firm Burton Group. IBM, CA and Novell are the other three.

"There is enormous overlap and there are going to be some tough questions there for Oracle," says Jamie Lewis, president of the Burton Group. "Customers are going to be concerned where their future lies."