Lesson 1

As the creator of the world's leading database product, Oracle has led the way in implementing distributed database connectivity. The lessons in this module examine the evolution of Oracle distributed networking and look at the basic features of the main Oracle network tools. These include:

1. Network protocols: We will look at basic computer protocols such as TCP/IP and SPX, and how Oracle enables inter-protocol communications.
2. Oracle Topology Solution: We will look in general terms at Oracle's topology solution and how the Oracle tools fit together.
3. Oracle Transparent Network Substrate model: This involves a technical overview of TNS and a description of the communication layers.

In addition, we will take a technical look at the internal features of each tool and lay the foundation for the detailed information later in this series.

Oracle's network interface knwown as Oracle Net, was formerly known as Net8 when used in Oracle8, and SQL*Net when used with Oracle7 and previous versions of Oracle. You can use the term Oracle Net over a wide variety of network protocols, although TCP/IP is by far the most common protocol today. Features associated with Oracle Net, such as shared servers, are referred to as Oracle Net Services.

To upgrade from SQL*Net release 2.x to Oracle Net Services or upgrade from Net8 release 8.0 or 8.1, complete these tasks:

• Step 1: Verify Service Name and Instance Name
  If you want to identify a service and its instance in the tnsnames.ora file, ensure that the SERVICE_NAMES and INSTANCE_NAMES initialization parameters are set in the initialization parameter file.
• Step 2: Perform Software Upgrade on the Database Server To perform a software upgrade on the database server, install the latest release of Oracle Net and Oracle Net Listener from the Oracle Universal Installer to receive the latest executables. You are prompted to upgrade a database with the Database Upgrade Assistant if the Oracle Universal Installer detects a pre-release 9.2 database on your system. If you do not want to upgrade during the installation process, then you can choose to install this assistant and use it later. The Oracle Universal Installer automatically performs these tasks:
  1. Stops older listener
  2. Starts release 9.2 listener
• Step 3: Perform Software Upgrade on the Client
  To perform a software upgrade on the client, install the latest release of Oracle Net Services from the Oracle Universal Installer to receive the latest executables.
• Step 4: Perform Functional Upgrade:
  After the software is upgraded, it is not required to upgrade the configuration files unless you want to use the Oracle9i features. To take advantage of new features, review the following configuration files:
  1. sqlnet.ora
  2. tnsnames.ora
  3. listener.ora
  4. protocol.ora
  Replace obsolete or renamed parameters.

Replace the SID parameter with the SERVICE_NAME parameter to connect to a release 8.1 or higher service, as in the following example.

sales=
(DESCRIPTION=
(ADDRESS=(PROTOCOL=tcp)(HOST=sales-server)(PORT=1521))
(CONNECT_DATA=
(SERVICE_NAME=sales.us.example.com)))

If you have multiple addresses, you can configure client load balancing and connect-time failover features, as in the following example.

sales=
(DESCRIPTION=
(ADDRESS_LIST=
(FAILOVER=on)
(LOAD_BALANCE=on)
(ADDRESS=(PROTOCOL=tcp)(HOST=sales1-server)(PORT=1521)
(ADDRESS=(PROTOCOL=tcp)(HOST=sales2-server)(PORT=1521))
(CONNECT_DATA=
(SERVICE_NAME=sales.us.example.com)))