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CHAPTER 20

Advanced Oracle Networking

In this chapter

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Understanding Enterprise Networking

The Oracle database is capable of supporting many different environments, from small workgroups supporting tens of users and hundreds of megabytes of data, to enterprise applications with thousands of simultaneous users, gigabytes of data, and hundreds of transactions per second. In a similar vein, Oracle networking is designed to support both the smallest and largest environments. If your needs are simple, your Oracle networking components can be configured so that one person can easily administer them with a minimum of time and effort. For larger installations with more complex implementations, the same concepts used in a small installation can be built on and expanded to support more challenging requirements. In this chapter, you look at some of the features of SQL*Net and Net8 that enable it to serve the needs of the enterprise.

Configuring SQL*Net and Net8

Unfortunately, installing the SQL*Net networking software is the least of your Oracle networking administrative duties. SQL*Net software must be carefully configured before it can be used, both on client and server machines. There are, in general, two accepted methods of configuring SQL*Net—through manual editing of the correct configuration files, or through the usage of the supplied Oracle configuration tools, Network Manager for Oracle7 and Net8 Assistant in Oracle8.

Oracle recommends configuration of the SQL*Net configuration files only through the supplied configuration. However, experienced (or impatient!) network administrators are often more comfortable making configuration changes directly to the configuration files. Also, there are times when the only way to configure a brand-new networking product, or enable a feature, is through direct configuration file manipulation. For these reasons, it is highly recommended that you at least familiarize yourself with the configuration files involved in SQL*Net and Net8 communication.

NOTE
Currently, the Network Manager and Net8 Assistant utility will not edit configuration files that have been modified by hand. Therefore, you must make the choice to either use the tool, or not to use the tool.

The easiest and most foolproof way to configure SQL*Net is with the Network Manager utility. In most cases, configuring your network resources using the Network Manager or Net8 Assistant is simply a matter of choosing the appropriate icon and filling in a few parameter values. The way these tools work is that the network configuration is stored internally. Based upon the Oracle resources you have created (such as Listeners, Names Servers, Databases, and so on), the appropriate configuration files for clients and servers are generated when you execute the utility. You are then responsible for placing these generated configuration files in the appropriate directories on the client or server.

The Net8 Assistant is different from Network Manager in that it is a Java application, and as such can run on any platform that has the appropriate Java runtime environment installed.

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It also contains additional functionality not found in Network Manager, as well as support for new Net8 features, such as the Connection Manager and the Advanced Networking option.

Using the Oracle Tools to Configure Oracle Networking

The following step-by-step explanation will create a simple Oracle network using the Network Manager tool. We will create a Oracle network consisting of a database server, a Listener, a database, and a Names server. Note that placing your mouse cursor over a button will cause a message explaining the button's purpose to appear. All of the button's functionality can also be performed using menu items. Complete the following steps:

  1. Start the Network Manager utility. With some versions, you will be asked where you would like to store the Network Definition: Select File.
  2. Select File, New, or press the Create A New Network Definition button. The utility will ask whether you want to perform a walk-through; select No.
  3. Press the Community button, and enter a name for the community. In Oracle terms, a community is one or more network resources that use the same protocol, and the community name should reflect the protocol name. Choose the correct protocol from the Protocol drop-down list, and press OK. Notice how each component of the network appears in the box at the left of the Network Manager screen as you create it, and the network resources contained within each highlighted container object appear in the box at the right.
  4. Press the Node button. A Node is a computer that houses an Oracle resource, such as a database or listener. Enter the name of the Node (the computer name), and select the Node type from the Node drop-down list. You will also need to select the community the Node belongs to by selecting the Community tab and adding the correct Community.
  5. Press the Listener button. As you can see, the Listener has many configurable options, but most of them are related to optional behavior, such as logging levels and monitoring. The name will default to Listener, and unless there are multiple listeners for the server, there is no need to change this value. The first Node will automatically appear in the Node box; select the correct Node if necessary. You can also assign a password to the Listener, which will be used when attempting to perform administrative tasks on the Listener. For now, the other parameter values can be left at their defaults.
    b. Select the Addresses tab. The address will specify the hostname and port on which the Listener will listen at. The default is 1521 or 1526, depending on the server type, and in most cases the default is fine. Press the Create button and accept the default values by hitting OK.
    c. Select the Databases tab. Here you specify what databases the Listener will listen for. You can only specify databases that reside on the Node the Listener resides on. If you have databases already created, you can select them from the Available list. Otherwise, press OK to create an empty Listener. We will assign databases to it in the next step. One quirk of Network Manager is that you cannot create databases on a Node without first creating a Listener on that Node.

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