SQL-Net-stacked  Oracle Net Services



Oracle Net Services provides a scalable, secure, and easy-to-use high-availability network infrastructure for Oracle environment. It eases the complexities of network configuration and management, maximizes performance, and improves network security and diagnostic capabilities as summarized hereafter.

  • Connectivity: Oracle Net Services enables a network session from a client application to an Oracle database server. Once a network session is established, Oracle Net acts as the data courier for both the client application and the database server. It is responsible for establishing and maintaining the connection between the client application and database server, as well as exchanging messages between them.
  • Manageability: it encompasses location transparency, centralized configuration and management, quick installation and configuration.
    • Location Transparency service allows a database client to identify the target database server; to achieve this goal, several naming methods are available today: Oracle Net Directory naming, Local naming (TNSNAMES.ORA), Host naming, and External naming.
    • Centralized Configuration and Management: allows administrators, in large network environments, to easily access a centralized repository (i.e., LDAP-compliant directory server such as Oracle Internet Directory) to specify and modify the network configuration.
    • Quick Installation and Configuration: networking components for the Oracle database server and clients are preconfigured for most environments. The Oracle database service is resolved using various naming methods. As a result, clients and servers are ready to immediately connect when installed.
  • Performance and Scalability: features such as Database Resident Connection Pool (connection pooling), Shared Server (session multiplexing), and scalable event models (polling) enable performabce and high scalability.
  • Network Security: Oracle Net Services enables database access control using features of firewall access control and protocol access control.
  • Diagnosability: a diagnostic and performance analysis tool, Trace Assistant, provides detailed information about the source and context of problems as they arise.

What's New in Oracle Database 12c

The new features for Net Services in Oracle Database 12c include:
  • Internet Protocol Version 6 (IPv6) Addressing and Connectivity support over Public VIPs to Real Application Clusters  (please refer the IPv6 Statement of Direction below for more information)
  • Networking support for new architectures, such as, Database Consolidation and Global Data Services
  • 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 bandwidth in networks that have high bandwidth delay products and host resources, according to application characteristics.
  • Advanced Network Compression. This feature can be used to reduce the amount of data transmitted over the network. New parameters for the sqlnet.ora file enable compression and selection of the preferred compression level. Please refer the Advanced Network Compression white paper below for more information.
  • Dead Connection 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 at a per-connection level.
  • Intelligent Client Connection establishment feature reduces the priority of connection attempts to unresponsive nodes in the address string of connect descriptors. No configuration changes are required to use this feature.
  • Incident Generation for Process Failures for the following Oracle Net Services components has been added:
    • Oracle Net Listener
    • Listener control utility (LSNRCTL)
    • Connection Manager Administration (CMADMIN)
    • Oracle Connection Manager gateway (CMGW)

What's New in Oracle Database 11gR1 & 11gR2

The new features for Net Services in Oracle Database 11g Release 2 include:

  • Internet Protocol Version 6 (IPv6) Addressing and Connectivity for single-instance database (please refer the IPv6 Statement of Direction below for more information)
  • Oracle Restart in single instance environment for restarting the listener, the database and other Oracle components following hardware/software failure or host restart.
  • Support for CONNECT_TIMEOUT and TRANSPORT_CONNECT_TIMEOUT for each IP address
  • CIDR notation and wildcard support for valid node checking

The new features for Net Services in Oracle Database 11g Release 1 include:

  • Support for authenticated LDAP access for Net Naming
  • Performance Improvements
    • Fastpath for common usage scenarios, enforced transparently (no configuration required)
    • Efficient network support for bulk/large data transfers (such as, SecureFile LOBs)
    • Efficient event dispatch mechanisms for PHP and process-based systems (enforced transparently, no config. required)
  • Fast Reconnects for High Availability: efficient detection of terminated instances and conect time failover
  • Support for Database Resident Connection Pool
  • Enhancements to the Easy Connect Naming method

For more details see the Oracle Database Net Services Administrator's Guide


Technical Information

Oracle OpenWorld
 Oracle Net Services 12c: Best Practices for Database Performance and Scalability
Oracle Database 12c
 Oracle Database and IPv6 Statement of Direction
 Advanced Network Compression
 Dead Connection Detection
Oracle Database 11gR2
 Application Failover in Oracle Database 11g
Oracle Database 11gR1
 Authenticated LDAP Name Lookup (PDF)
 Configuring Microsoft Active Directory 2003 for Net Naming (PDF)
 Oracle Net Listener Connection Rate Limiter (PDF)
 Oracle Easy Connect Naming (PDF)
Oracle Database 10g
 Oracle Net Services Overview for Oracle10g (PDF)
 Oracle Net High-Speed Interconnect Support (PDF)
 Oracle Connection Manager Overview (HTML)
Oracle Database 9i
 Oracle Net Services New Features Overview (HTML)
 Directory Naming Migration: New Features and a Case Study (PDF)
 Migrating from Oracle Names and Local Naming to Directory Naming (PDF)


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