Figure 21–1 shows the basic Instant Messaging architecture.
Instant Messaging server and one or more Instant Messaging multiplexors
Instant Messaging resources
Web server such as Sun Java System Web Server
LDAP server such as Sun Java System Directory Server
In this example:
The LDAP server provides user entries for authentication and lookup.
The clients download the Instant Messaging resources from either a web server or Sun Java System Application Server
Clients always connect to the Instant Messaging server through an Instant Messaging multiplexor.
Figure 21–2 shows the interaction of the software components in the authentication process of a basic architecture of Instant Messaging. The focus is on the flow of authentication requests. An explanation of the steps in this process follows the figure.
The authentication process in a basic architecture works as follows:
Java Web Start or the Java plugin downloads the necessary Instant Messenger resource files and starts Instant Messenger.
The login window appears and the end user enters the login name and password. The login data is sent to the Instant Messaging server through the multiplexor.
The Instant Messaging server communicates with the LDAP server to authenticate the end user and to request end-user information, such as contact lists or subscriptions.
When the end-user authentication is complete, the Instant Messaging main window appears, displaying the contact list for the end user. The end user can now start and participate in Instant Messaging sessions with the other end users.