Oracle is constantly making enhancements to Net, and the Net listener is no exception. The Oracle listener still serves the same basic function of listening for incoming database connections and establishing connections to the Oracle database, but the enhancements in Oracle provide more robust listener-process management and more reliability, as described in the list below.

1. New initialization parameters: To take advantage of many of the new features of Net, you must add some new initialization parameters, such as SERVICES_NAMES and INSTANCE_NAMES, when starting up your database.
2. Changes to the tnsnames.ora file format: The file that specifies which database nodes are available through Net listener has been revised to handle new features of Net.
3. Net Configuration Assistant: This assistant has been enhanced to support new Net and Oracle features so that it can be used to configure listeners, naming methods, Net service names, and LDAP directory service.
4. Multiple services for one database instance: The service name replaces the service identification (SID) in Oracle. This allows one database instance to have several services, enabling a listener to access the database as if it were two databases.
5. Multiple database instances for one service: Oracle uses the service name to consolidate many databases into one service. A service can connect database instances on different nodes.

The next lesson looks at Net Services scalability features.

Oracle Net Services provides enterprise wide connectivity solutions in distributed, heterogeneous computing environments. Oracle Net Services ease the complexities of network configuration and management, maximize performance, and improve network diagnostic capabilities. This module introduces the basic networking concepts involved in a typical network configuration. The topics include:

1. Connectivity
2. Manageability
3. Internet and Intranet Scalability
4. Performance Between the Middle Tier and Oracle Database
5. Network Security

Oracle Net, a component of Oracle Net Services, enables a network session from a client application to an Oracle Database server. Once a network session is established, Oracle Net acts as the data courier for both the client application and the database server. It is responsible for establishing and maintaining the connection between the client application and database server, as well as exchanging messages between them. Oracle Net is able to perform these jobs because it is located on each computer in the network.