USE_SHARED_SOCKET
You can set the USE_SHARED_SOCKET parameter 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 need to 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 dedicated server mode in a TCP/IP environment. If this parameter is set, you cannot use the 9.0 listener to spawn Oracle 7.x databases. To spawn a dedicated server for an Oracle database not associated with the same Oracle home as the listener and have shared socket enabled, you must also set the variable USE_SHARED_SOCKET for both Oracle homes.