connect descriptor

A specially formatted description of the destination for a network connection. A connect descriptor contains destination service and network route information.

The destination service is indicated by using its service name for the Oracle Database or its Oracle system identifier (SID) for Oracle release 8.0, or version 7 databases. The network route provides, at a minimum, the location of the listener through use of a network address.

default domain

The network domain within which most client requests take place. It can be the domain where the client resides, or a domain from which the client often requests network services. The default domain is also the client configuration parameter that determines what domain to append to unqualified network name requests. A name request is unqualified if it does not have a "." character within it.

easy connect naming

A Naming method that allows clients to connect to a database server without any configuration. Clients use a simple TCP/IP address, which consists of a host name and optional port number, service name, and instance name:

SQL>CONNECT user_name@host[:port][/service_name][/instance_name]
Enter password: password

installation type

An installation type is a predefined component set that automatically selects which components to install. See "Oracle Database Client Installation Types" for a list of installation types available with each top-level component.

Interprocess Communication (IPC)

A protocol used by client applications that resides on the same node as the listener to communicate with the database. IPC can provide a faster local connection than TCP/IP.

ldap.ora file

A file created by the Oracle Net Configuration Assistant that contains the following directory access information:

  • Type of directory

  • Location of directory

  • Default administrative context the client or server uses to look up or configure connect identifiers for connections to database services

The ldap.ora file resides in ORACLE_HOME\network\admin.


A process that resides on the server and whose responsibility is to listen for incoming client connection requests and manage the traffic to the server.

When a client requests a network session with a database server, a listener receives the actual request. If the client information matches the listener information, then the listener grants a connection to the database server.

listener.ora file

A configuration file for the listener that identifies the:

  • Listener name

  • Protocol addresses on which it is accepting connection requests

  • Services for which it is listening

The listener.ora file resides in ORACLE_HOME\network\admin.

An Oracle Database 12c Release 1 (12.1) does not require identification of the database service because of service registration. However, static service configuration is required for an Oracle Database 12c Release 1 (12.1) if you plan to use Oracle Enterprise Manager.

local naming

A Naming method that resolves a net service name into a connect descriptor. This name is configured and stored in the tnsnames.ora file on each individual client.

Naming method

A resolution method used by a client application to resolve a connect identifier to a network address when attempting to connect to a database service. Oracle Net Services supports the following naming methods:

  • Local naming

  • Directory naming

  • Easy Connecting naming

  • NIS External naming

net service name

A simple name for a service that resolves to a connect descriptor. Users initiate a connect request by passing a username and password along with a net service name in a connect string for the service to which they want to connect:

SQL> CONNECT username@net_service_identifier
Enter password: password

Depending on your needs, net service names can be stored in a variety of places, including:

  • Local configuration file, tnsnames.ora, on each client

  • Directory server

  • External naming service, such as Network Information Service (NIS) or Cell Directory Service (CDS)

operating system authenticated connections

Windows login credentials can be used to authenticate users connecting to an Oracle Database. The benefits of Windows native authentication include:

  • Enabling users to connect to multiple Oracle Databases without supplying a username or password

  • Centralizing Oracle Database user authorization information in Windows, which frees Oracle Database from storing or managing user passwords


The initialization file parameter OS_AUTHENT_PREFIX enables users to specify a prefix that Oracle uses to authenticate users attempting to connect to the database. Oracle concatenates the value of this parameter to the beginning of the user's operating system account name. When a connection request is attempted, Oracle compares the prefixed username with Oracle usernames in the database.

The default value of this parameter is "" (a null string), thereby eliminating the addition of any prefix to operating system account names. In earlier releases, OPS$ (short for operating system specific) was the default setting.

Oracle Context

The root of a directory subtree with a relative distinguished name of cn=OracleContext, under which all Oracle software information is kept. There may be one (or multiple) Oracle Context in a directory. An Oracle Context can be associated with a directory naming context.

The Oracle Context can contain the following Oracle entries:

  • Connect identifiers for use with Oracle Net Services directory naming to make database connections

  • Enterprise user security for use with Oracle Advanced Security

Oracle home

The directory path to install Oracle components (for example, c:\app\username\product\12.1.0\dbhome_n where n is the number of the Oracle home). You are prompted to enter an Oracle home in the Path field of the Oracle Universal Installer File Locations window.

Oracle schema

A set of rules that determine what can be stored in an LDAP-compliant directory server. Oracle has its own schema that is applied to many types of Oracle entries, including Oracle Net Services entries. The Oracle schema for Oracle Net Services entries includes the attributes the entries may contain.

Oracle Net foundation layer

A networking communication layer that is responsible for establishing and maintaining the connection between the client application and server, and exchanging messages between them.

protocol address

An address that identifies the network address of a network object.

When a connection is made, the client and the receiver of the request, such as the listener, or Oracle Connection Manager, are configured with identical protocol addresses. The client uses this address to send the connection request to a particular network object location, and the recipient "listens" for requests on this address. It is important to install the same protocols for the client and the connection recipient, as well as configure the same addresses.


A set of tables located in any Oracle database accessible to the Oracle Management Server. Oracle Management Server uses a repository to store all system data and application data, information about the state of managed nodes distributed throughout the environment, as well as information about the separately licensable management packs.

service registration

A feature by which the LREG process (an instance background process) automatically registers information with a listener. Because this information is registered with the listener, the listener.ora file does not need to be configured with this static information.

Service registration provides the listener with the following information:

  • Service name(s) for each running instance of the database

  • Instance name(s) of the database

  • Service handlers (dispatchers and dedicated servers) available for each instance

    This allows the listener to direct a client's request appropriately.

  • Dispatcher, instance, and node load information

    This allows the listener to determine which dispatcher can best handle a client connection's request. If all dispatchers are blocked, the listener can spawn a dedicated server for the connection.

This information allows the listener to determine how best to service a client connection request.


The Oracle system identifier that distinguishes the database from all other databases on your computer. The SID automatically defaults to the database name portion of the global database name (sales in the example until you reach eight characters or enter a period. You can accept or change the default value.

sqlnet.ora file

A configuration file for the client or server that specifies the:

  • Client domain to append to unqualified service names or net service names

  • Order of naming methods for the client to use when resolving a name

  • Logging and tracing features to use

  • Route of connections

  • External naming parameters

  • Oracle Advanced Security parameters

The sqlnet.ora file resides in ORACLE_HOME\network\admin.

system identifier

See SID.

Terminal Server

Microsoft Windows Terminal Server is a Windows thin-client terminal server, a product that adds support for multiple, simultaneous client sessions on the Windows Server. Windows Terminal Server provides an operating system graphical user interface (GUI) to users of Oracle databases.

tnsnames.ora file

A configuration file that contains net service names mapped to connect descriptors. This file is used for the local naming method. The tnsnames.ora file resides in ORACLE_HOME\network\admin.

typical configuration

Oracle Universal Installer option that performs a default configuration of a connection between Oracle Database Client and Oracle Database. It configures the following:

When Oracle Database Client attempts to connect, it tries local naming first, followed by easy connect naming.

unqualified name

A net service name that does not contain a network domain.

Universal Naming Convention (UNC)

The Universal Naming Convention provides a means to access files on a network without mapping the network drive to a drive letter. UNC names are constructed in the following manner:

\\computer name\share name\filename

User Account Control

A Microsoft Windows feature that helps prevent unauthorized changes by asking for permission or administrator privileges to perform certain operations. Some Oracle administration tasks require Windows administrator privileges granted through User Account Control.