You can use the parameter LOCAL to connect to Oracle Database without specifying a connect identifier in the connect string.

The value of the parameter LOCAL is any connect identifier, such as a net service name. For example, if the parameter LOCAL is specified as finance, you can connect to a database from SQL*Plus with:

SQL> CONNECT SMITH
Enter password: password

rather than

SQL> CONNECT SMITH@finance
Enter password: password

Oracle Net checks if LOCAL is defined as an environment variable or as a parameter in the registry, and uses finance as the service name. If it exists, then Oracle Net connects.

You can add the parameter TNS_ADMIN to change the directory path of Oracle Net Services configuration files from the default location of ORACLE_HOME\network\admin.

For example, if you set TNS_ADMIN to ORACLE_HOME\test\admin, then the configuration files are used from ORACLE_HOME\test\admin.

You can set the parameter USE_SHARED_SOCKET to true to enable the use of shared sockets.

If this parameter is set to true, the network listener passes the socket descriptor for client connections to the database thread. As a result, the client does not establish a new connection to the database thread and database connection time improves. Also, all database connections share the port number used by the network listener, which can be useful if you are setting up third-party proxy servers.

This parameter only works in the dedicated server mode in a TCP/IP environment. If this parameter is set, you cannot use the Oracle database listener to spawn Oracle Database. To spawn a dedicated server for an instance of Oracle Database not associated with the same Oracle home as the listener and have shared socket enabled, you must also set parameter USE_SHARED_SOCKET for both Oracle homes.