Multiplexing 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:
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:
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.
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.
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:
one for the Connection Manager and
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.
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.