What is SQL*Net/ Net8?

Net8 (called SQL*Net prior to Oracle8) is Oracle's client/server middleware product that offers transparent connection from client tools to the database, or from one database to another.

Net8 enables services and their applications to reside on different computers and communicate as peer applications. The main function of Net8 is to establish network sessions and transfer data between a client machine and a server or between two servers. Net8 is located on each machine in the network. Once a network session is established, Net8 acts as a data courier for the client and the server.

Essentially, SQL*Net provides the software layer between Oracle and the networking software, providing seamless communication between an Oracle client machine (running, for example, SQL*Plus) and the database server or from one database server to another. SQL*Net/ Net8 works across multiple network protocols and operating systems.

TNS or Transparent Network Substrate is Oracle's networking architecture. TNS provides a uniform application interface to enable network applications to access the underlying network protocols transparently.

The TNS architecture consists of three software components:

• TNS-based applications (like SQL*Plus or TOAD)
• Oracle Protocol Adapters (OPA)
• Networking software like TCP/IP