Oracle Net (known as Net8 for Oracle8 and Oracle8i and SQL*Net prior to Oracle8) is a layer of software that allows different physical machines to communicate for the purpose of accessing an Oracle database.
The name Net8 has been changed to Oracle Net in Oracle9i, and we will generally use “Oracle Net” in this chapter as a neutral term to apply to all versions of Oracle networking. The term "Oracle Net services” in Oracle9i refers to all the components of Oracle Net, including dispatchers, listeners, and shared servers; these are explained later in this chapter.
A version of Oracle Net runs on the client machine and on the database server, and allows clients and servers to communicate over a network using virtually any popular network protocol (e.g., TCP/IP, LU6.2, DECNET, and SPX/IPX). Oracle Net can also perform network protocol interchanges. For example, it allows clients that are speaking SPX/IPX to interact with database servers that are speaking TCP/IP.
Oracle Net also provides location transparency—that is, the client application does not need to know the server’s physical location. The Oracle Net layer handles the communications, which means that you can move the database to another machine and simply update the Oracle Net configuration details accordingly. The client applications will still be able to reach the database, and no application changes will be required.
Oracle Net introduces the notion of service names, or aliases. Clients ...