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Lesson 3 Oracle Net multiplexing
Objective Configure Oracle Net for multiplexing.

Oracle Net Multiplexing Configuration

Multiplexing[1] was a feature introduced in Oracle8i. Multiplexing is also called connection concentration, which means that it requires that you have a Multi-Threaded Server (such as Oracle Shared Server) and that you configure Oracle Net and the Connection Manager to handle multiplexing.

Configuring the Oracle Database Server

In addition to setting up the usual MTS parameters, you must add this parameter anywhere in your init.ora file:
MULTIPLEX=YES

This tells the server to allow multiplexed connections from the Connection Manager.

Configuring the Connection Manager

Use the standard configuration for the Connection Manager, as described in the previous lesson. All the default settings are valid.
The following parameters may require adjustments to support the kind of environment you have at your site:
  1. MAXIMUM_RELAYS:This parameter can range from 1 to 2048. It specifies the maximum number of concurrent connections that can be handled by the Connection Manager. The default value is 128.
  2. ANSWER_TIMEOUT: This parameter can range from zero to any number of seconds. The default value is zero. This parameter determines the number of seconds to wait before Connection Manager ends an attempt to make a handshake contact with an incoming connection.
  3. AUTHENTICATION_LEVEL: This parameter tells the Connection Manager about security. A zero (the default) tells the Connection Manager to accept any request coming into its port. A number 1 tells the Connection Manager to only accept (SNS) Secure Network Services requests. SNS is one of the Oracle Advanced Security (OAS) options.
If you need values other than the default values, you must create a cman.ora file and specify the values of these parameters.

Configuring Oracle Net

You will need to configure two addresses for the database:
  1. one for the Connection Manager and
  2. one for the Oracle Net listener.

This requires modifying the tnsnames.ora file. The following diagram explains the components of the file that you need.
  1. Tell the listener to start with the first address when connecting to the database
  2. This is the address of the Connection Manager. It uses the default port number (1630).
  3. This is the address of the Net8 Listener. It will not be used unless the Connection Manger is shut down.

Configuring tnsnames.ora File for Multiplexing
Once you have configured the Net8 listener and the Connection Manager, you must start up the Connection Manager and the listener.
After that, your listener will route all transactions through the Connection Manager.
The next lesson covers connection pooling.

Configure Oracle Multiplexing

Click the link below to read about configuring multiplexing.
Configure Oracle Multiplexing
[1]Multiplexing: Combining several individual transmissions and sending them across a single connection to and from a database.