Oracle Networking Products Getting Started for Windows Platforms
Release 8.0.3
A53746-01

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1
Overview of Oracle Networking

This chapter covers the following topics:

Oracle Connectivity Overview

The main function of Oracle Networking Products is to establish sessions and transfer data between a client and a server or between two servers. Once a session is established, Oracle Networking Products act as a data courier for the client and the server. The connection operation is initiated during any standard database login between the client application and the server, with information such as the client machine name and user name passed to the remote machine.

Sessions are established with the help of a listener. The listener brokers the client request, handing off the request to the server. Every time a client (or server acting as a client) requests a session with a server, a listener receives the actual request. The listener determines the location of the server and enables the client to connect to the server. The listener is a separate process whose responsibility is to listen for incoming client connection requests and manage the traffic to the server.

Architectural Overview

Net8, the networking layer formerly known as SQL*Net, uses the Transparent Network Substrate (TNS) and standard industry network protocols to connect a client to a server and establish an Oracle session. The following figure shows the basic connectivity architecture and process, with a connection request originating from a client side application. The database returns the queried information in the reverse direction.

Following is an overview of the Oracle network connectivity components:

Net8
Oracle Protocol Adapters
Network-Specific Protocol Stack (third-party component)

Net8

Net8 is a software layer that is required to communicate between Oracle clients and servers.The role of Net8 is to establish and maintain a connection between the client application and the server and exchange messages between them. It provides both client to server and server to server communications across any network. It enables client tools to access, modify, share, and store data on Oracle8 Servers over a network. The communication between client applications and servers takes place across one or more networks and is referred to as client/server communication.

Transparent Network Substrate (TNS)

The TNS is an underlying layer of Net8 that receives requests and settles all generic connectivity functions such as opening and closing a session or sending and receiving requests or responses. TNS then passes control to an Oracle Protocol Adapter to make the protocol-specific call.

Oracle Protocol Adapters

The Oracle Protocol Adapters are responsible for mapping TNS functionality to industry-standard protocols used in the client/server connection. Each adapter is responsible for mapping the equivalent functions between TNS and a specific protocol.

An Oracle Protocol Adapter translates (or adapts):

function calls of specific network protocols (such as TCP/IP) into equivalent function calls of the Oracle Transparent Network Substrate (TNS).
TNS generic function calls into specific function calls for the underlying network protocol.

Additional Information:

See

the third-party network documentation that came with your protocol software for a detailed technical discussion of these protocols.
Chapter 2, "Introducing Oracle Networking Products" for a list of available protocol adapters.

Network-Specific Protocol Stack

The protocol stack (third party software) supplies a reliable means of communication across the network. All Oracle software in the client/server connection process requires an existing network protocol stack to make the machine-level connection between two machines. The network protocol is responsible only for getting the data from the client machine to the server machine, at which point the data is passed to the Oracle Protocol Adapter on the server side.

Client/Server Interaction

This section describes a basic client/server connection.

Client Request

The user requests a database connection from the server by supplying input (SQL command) through a client side application such as SQL*Plus. The application sends the request to Net8 to be transported across the network to the server. After the connection request is accepted by the listener on the server, the client application requests database information from the server.

Server Response to Client Request

The server runs the Oracle8 database software and a Net8 network listener program. The Net8 network listener, through an Oracle Protocol Adapter, accepts connections from client applications on the network.

Net8 on the server delivers the client data transfer request to the Oracle8 database. The database performs the function requested by the user on the client machine. Finally, Net8 transfers the results of the database functions to the client machine.

Planning a Network

Issue	Considerations
Define the network layout	What functionality is required by the client applications in your network? Which protocol should I use? What is the anticipated network traffic?
Organizing and naming network components	Does the network need a flat naming model or an hierarchical naming model? Will I use multiple administrative regions?
Resolving service name addresses	Which naming method should I use? host naming external naming centralized naming using oracle names local naming
Managing connection requests	How will the network listener accept connection requests? dedicated server process prestarted or prespawned server processes shared or dispatcher server processes (multi-threaded server (MTS))
Improving network performance	How can I improve network performance? connection pooling (MTS) multiplexing (MTS) load balancing adjusting the session data unit (SDU) size persistent buffer flushing increasing the listener queue size