Oracle Net is the communication software that enables a network session between a client application and an Oracle database. After a network session is established, Oracle Net acts as a data courier for the client application and the database.
The following are the new features in Oracle Net Services:
Larger Session Data Unit Sizes
Oracle Net 12c supports large session data unit (SDU) sizes, with a new upper limit of 2 MB. The larger SDU size can be used to achieve better utilization of available network bandwidth in networks that have high bandwidth-delay products and host resources, according to application characteristics.
Advanced Network Compression
Advanced Network Compression is another new feature that reduces the amount of data transmitted over the network. New parameters for the sqlnet.ora file enable compression and selection of the preferred compression level. Advanced Network Compression is available as part of the “Advanced Compression Option”.
Terminated Client Detection
Terminated client detection has been enhanced to reduce the amount of time taken to detect terminated connections. The SQLNET.EXPIRE_TIME parameter must be set in the sqlnet.ora file to detect terminated clients. If the system supports TCP keepalive tuning, then Oracle Net Services automatically uses the enhanced detection model, and tunes the TCP keepalive parameters.
Intelligent Client Connection
This feature reduces the priority of connection attempts to unresponsive nodes in the address string of connect descriptor. No configuration changes are required to use this feature.
Incident Generation for Process Failures
In case of a process failure, an incident is generated for the following Oracle Net Services components:
- Oracle Net Listener
- Listener control utility (LSNRCTL)
- Connection Manager Administration (CMADMIN)
- Oracle Connection Manager gateway (CMGW)
An incident includes the call stack as well as diagnostic information. Incident generation works with Automatic Diagnostic Repository (ADR) to organize the dump information for critical errors into incidents. If ADR is disabled, then incident generation is also disabled.
Valid Node Checking for Registration
Oracle Net Listener allows screening of service registration requests from database instances. A database instance is allowed to register services if the instance is running on a valid node. Database administrators specify a list of valid nodes and excluded nodes. The list of valid nodes specifies hosts and subnets from which instances can register services with the listener. The list of excluded nodes specifies hosts and subnets from which instances are not allowed to register services with the listener. The database administrator can also disable valid node checking.
By default, valid node checking for registration (VNCR) is enabled, and registration is allowed from instances running on the local host. Subnets or remote hosts need to be configured in the list of valid nodes. This configuration is performed automatically for Single Client Access Name (SCAN) listeners as part of an Oracle Real Application Clusters installation.
Support of Oracle Home User on Windows
Starting with Oracle Database 12c Release 1 (12.1), Oracle Database supports the use of Oracle Home User, specified at the time of installation. Oracle Home User is used to run Windows services for the Oracle Home. Oracle Home User is associated with an Oracle home and cannot be changed post installation. On a system, different Oracle homes can share the same Oracle Home User or use different Oracle Home User names.
Oracle Home User can be a Windows built-in account or a Windows User Account. For enhanced security, Oracle recommends that the standard Windows User Account be chosen as the Oracle Home User for Oracle Database installations. The primary purpose of Oracle Home User is to run Windows services with Windows User Account. This user account (Oracle Home User) must be a standard Windows user account (not an Administrator). Windows User Account can be a Local User, a Domain User, or a Managed Services Account.