This illustration shows where the listener fits into a client/server application connection.
The client shows a communication stack. From the top down, the stack is constructed with the following layers:
It shows a listener receiving the client connection on the database server. The database server shows a communication stack that includes two layers. From the top down, the stack is constructed with the following layers:
The TCP/IP network protocol resides between the client and the database server.
During a connection, the client application communicates with the Oracle Net layer. In turn, Oracle Net communicates with the TCP/IP protocol, which passes the connection to the Oracle Net layer on the database server.