This figure consists of three columns and shows the following:

• Client Tier:

(The figure shows a browser client on a computer, cell phone, and Personal Digital Assistant.)

• Middle Tier: Multiple instances of J2EE and Web Cache can coexist one Host.

(The figure shows one instance of J2EE and Web Cache on Host 1and multiple instances of J2EE and Web Cache on one Host2.)
 
• Infrastructure: Further enables J2EE and Web Cache.

(The figure shows an instance of Oracle9iAS Infrastructure on a Host 3 with Oracle9iAS Metadata Repository, Oracle9iAS Single Sign-On, Oracle Internet Directory, and Oracle Management Server.)