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Lesson 3 View the Net Assistant
Objective Add a network node in Net Assistant.

View the Net Assistant

The "Net Assistant" was a GUI tool that helped DBA's configure Oracle communications. It supported wizards and configuration windows for the
  1. Net listener,
  2. Configuration Manager,
  3. Advanced Security, and
  4. Oracle database server nodes.
It read and modified the tnsname.ora file, the sqlnet.ora file, and the listener.ora file, which stored configuration parameters for Oracle communications. The "tns" in tnsnames stands for Transparent Network Substrate, which is the technology built into Network Services that allows it to communicate with any standard network protocol (like TCP/IP). Even though manually created configuration files could be read and modified by the Oracle8i Net Assistant, many DBA's continued to manually support their configuration files as they have in the past.

Using Oracle Net Configuration Assistant to Configure Network Components

Oracle Net Configuration Assistant configures basic network components during installation, including:
  1. Listener names and protocol addresses
  2. Naming methods the client uses to resolve connect identifiers to connect descriptors
  3. Net service names in a tnsnames.ora file
  4. Directory server usage

Oracle Net Configuration Assistant runs automatically during software installation, as described in the Oracle Database installation guide. It can also be run after installation in standalone mode to configure naming methods, the listener, network service names in the tnsnames.ora file, and directory server usage. To start Oracle Net Configuration Assistant do the following:
  1. On Linux and UNIX, run netca from the ORACLE_HOME/bin directory.
  2. On Microsoft Windows, select Programs from the Start menu, and then select Oracle - HOME_NAME.
Next, select Configuration and Migration Tools, and then Oracle Net Configuration Assistant.

Oracle Net Manager replaced Oracle's Net Assistant

> The technology introduced by Oracle to replace "Oracle's Net Assistant" in Oracle 8i was "Oracle Net Manager." Oracle Net Manager emerged as a more advanced and user-friendly tool, designed to enhance and simplify the configuration and management of network components in Oracle database environments. Oracle Net Assistant, used in Oracle 8i, was primarily a tool for configuring basic network components like 1) listeners and 2) naming methods. As Oracle's technology evolved, there was a growing need for a more robust and versatile tool to manage increasingly complex network configurations and to offer better support for new features and protocols.
Oracle Net Manager addressed these needs by providing a graphical interface that allowed for more intuitive and comprehensive management of network services. This tool made it easier to create, configure, and manage Oracle Net Services, including listeners, naming methods, and network profiles. Oracle Net Manager's capabilities extended to configuring advanced network features, such as connection load balancing, failover, and Oracle Connection Manager settings.
Key enhancements in Oracle Net Manager over Oracle's Net Assistant included:
  1. Improved User Interface: Oracle Net Manager offered a more streamlined and user-friendly interface, making it easier for database administrators to navigate and configure network settings.
  2. Advanced Configuration Options: It provided more advanced options for configuring network settings, including support for newer protocols and sophisticated network architectures.
  3. Enhanced Performance Tuning: Oracle Net Manager enabled better tuning of network parameters for optimal performance, particularly important in large and complex database environments.
  4. Integration with Other Oracle Tools: It was designed to work seamlessly with other Oracle database tools and technologies, offering a more integrated and cohesive management experience.
Oracle Net Manager thus played a crucial role in transitioning from the simpler network configurations of the past to the more sophisticated and demanding network environments, aligning with Oracle's overall progression towards more advanced and integrated database technologies.

As you probably realized, all this wizard does is make an entry in our tnsnames.ora file. Here is how it will appear after this session; note the new ADDRESS_LIST parameter. 
# E:\ORACLE\ORA81\NETWORK\ADMIN\
   TNSNAMES.ORA 
   Configuration
File:E:\Oracle\Ora81\NETWORK\ADMIN\
   tnsnames.ora
# Generated by Oracle Net Assistant

TESTDB =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = 
      CAROLSPC
      (PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = orcl.carol.org)
    )
  )

ORCL =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = 
      carolspc)
      (PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = orcl.carol.org)
    )
  )

As you can see, the Net Assistant was a great tool for making easy changes to the parameter files. Because each database server and Oracle Net client has a tnsnames.ora file, most organizations create a "master" tnsnames.ora file and "push" the file to clients on a periodic basis. Tivoli Courier is commonly used for this task, but other software distribution tools work just as well. Remember, there are two cases in which you should add a multiple-service name for a single database:
  1. When you want to define multiple listeners (on separate posts) for a single database
  2. When you are using OPS and you want to add a Net service to map a request to another Oracle instance
The next lesson explores the entries in the parameter file (tnsnames.ora) maintained by the Net Assistant.

Add Net Service

Add a Net service name by using the Oracle Net Configuration Assistant

Adding a Net Service Name using the Oracle Net Configuration Assistant (NetCA) is a systematic process integral to configuring client connections to Oracle databases. This service name is a key component of the Oracle Net environment, facilitating the resolution of a service name to a network address and other necessary connection information. Here’s a step-by-step guide to accomplish this:
  1. Launching Oracle Net Configuration Assistant:Start the Oracle Net Configuration Assistant (NetCA). This can typically be done from the Oracle program group in your operating system's start menu or through a command line interface by executing `netca`.
  2. Choosing the Operation:Upon launching NetCA, select the 'Local Net Service Name Configuration' option. This allows you to configure service names on the client machine.
  3. Creating a New Net Service Name:Choose the 'Add' option to initiate the process of adding a new Net Service Name.
  4. Entering the Net Service Name:You will be prompted to enter a 'Net Service Name'. This is a user-defined, logical name that refers to the specific Oracle database network service you intend to connect to. Choose a name that is easily identifiable and relevant to the database service.
  5. Selecting the Protocol:Select the appropriate network protocol that matches your network environment and database configuration. Commonly, this would be TCP/IP for most network environments.
  6. Specifying Database Host Details:Enter the hostname or IP address of the Oracle database server you wish to connect to. You will also need to provide the port number on which the Oracle database listener is running (the default port is typically 1521).
  7. Specifying the Database Service Name:Enter the service name of the Oracle database to which you want to connect. This service name is configured in the database and is used by the listener to route client connections to the correct database instance.
  8. Testing the Connection:After entering all the necessary details, you have the option to test the connection. This step is highly recommended to ensure that all parameters are correctly set and the client can successfully connect to the database server.
  9. Completing the Configuration:If the connection test is successful, proceed to complete the configuration. The Net Service Name you have created will be saved in the `tnsnames.ora` file, which is used by Oracle clients to resolve the service name to the network address of the Oracle database.
  10. Exiting NetCA:After successfully adding the Net Service Name, exit the Oracle Net Configuration Assistant.

This process effectively creates an alias that simplifies the connection process for Oracle database clients, making it easier for users and applications to connect to the database without needing to remember complex network addresses or other technical connection details.
Net Assistant
You completed the steps and created the following entry into the tnsnames.ora file: 
PETS_ATLANTA =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = ATLANTA.EPETS.COM)
        (PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = HOUSEOPETS)
    )
  )

Oracle Network Services

Oracle Network Services consists of three components:
  1. client:The client is the application or software that initiates the connection. It may be an end user application, such as a web page, or it may be another Oracle server.
  2. server: This is the software to which the client connects; it may be an Oracle server or an external procedure.
  3. listener: The listener (also known as the TNS listener or the Net Services listener) creates listen end points on the machine housing the Oracle server or external procedure. The addresses of these end points are established in advance and published in the tnsnames.ora file, stored in an Oracle Names server (the location of which is published in the names.ora file) or stored in some other name server.