Lesson 1

This module introduces the architecture of Oracle Net Services, the foundation for network communication in Oracle databases. We will explore the key components of Oracle Net Services and the essential parameter files used to configure and manage database connectivity. By understanding these elements, you will learn how Oracle Net establishes and maintains connections between clients and database servers.

Oracle Net Services relies on three core components to manage network communication:

• Oracle Net Services: The overarching framework that enables network communication between clients and Oracle databases. It provides the infrastructure for connection establishment, data transfer, and network management across distributed environments.
• Transparent Network Substrate (TNS): The core protocol within Oracle Net Services, responsible for handling name resolution, connection establishment, and data transfer between clients and the database server.
• Oracle Listener: A server-side process that listens for incoming client connection requests and directs them to the appropriate database instance.

Oracle Net Services is the comprehensive system, TNS is the protocol it uses to communicate, and the Listener acts as the intermediary directing connection requests.

Oracle Net Services uses several configuration files to define and manage network connectivity. This module will cover:

1. tnsnames.ora: A file that maps network service names to connect descriptors, allowing clients to connect to databases using simple aliases.
2. listener.ora: A server-side file that configures the Oracle Listener, specifying how it handles incoming connection requests.
3. protocol.ora: A file used to configure protocol-specific parameters for network communication (optional in most setups).
4. sqlnet.ora: A file that defines client and server network behavior, such as authentication, encryption, and naming methods.

These files work together to enable seamless database communication. While local configuration using these files is common, directory services (such as LDAP-compliant servers) can be used as an alternative for centralized name resolution.

After completing this module, you will be able to:

1. Describe the syntax and function of Oracle Net parameter files.
2. Define the components of Oracle network tools.
3. Describe the components and functions of the tnsnames.ora file.
4. Explain how the protocol.ora file operates.
5. Explain the purpose and uses of the sqlnet.ora file.
6. Establish Oracle Net communications at the process level.
7. Explain the purpose and syntax of Oracle database links.
8. Establish connections over database links.

We will begin by examining the syntax and function of the Oracle Net parameter files, followed by a detailed look at how these components and files enable database connectivity.