Three additional features of CMAN warrant detailed discussion.

Oracle Connection Manager enables you to take advantage of Net8's ability to multiplex or funnel multiple logical client sessions through a single transport connection to a multi-threaded server destination. This process is accomplished through Oracle Connection Manager's connection concentration feature.
Concentration reduces the demand on the resources needed to maintain multiple connections between two processes. It enables the server to use fewer connection end points for incoming requests while increasing the total number of sessions that a server can handle. By using multiple Connection Managers, it is possible for thousands of concurrent users to connect to a server.

Unlike a SQL*Net or Net8 listener, which accepts connections from any remote host, Oracle Connection Manager includes a feature you can use to control client access to designated servers in a TCP/IP environment. In other words, you can direct the CMAN software to reject connections from unknown clients.
By specifying certain filtering rules, you may allow or restrict client access to a server based on the following criteria:

1. Source hostname or IP address for clients
2. Destination hostname or IP address for servers
3. Destination database server identifier

Oracle Connection Manager also provides multiple protocol support enabling a client and server with different networking protocols to communicate with each other. This feature replaces functionality previously provided by the Oracle Multi-Protocol Interchange in SQL*Net version 2. Net8 can traverse as many networking protocol stacks as can be installed and supported. In fact, the number of networking protocols supported is limited only by those restrictions imposed by the specific node;s hardware, memory, and operating system.
Remember that CMAN is a new product within Oracle8 and it is intended to eventually replace the Net8 listener.
In the next lesson, you will find out how to configure the CMAN parameter file.