The two-tier and
three-tier connections use a network to communicate with the database, while the
local client uses local IPC.
72 | Chapter 3: Installing and Running Oracle
Oracle Net and Establishing Network Connections
The server processes shown in Figure 3-5 are connected to the client processes using
some kind of network. How do client processes get hooked up with Oracle server
processes to begin working?
The matchmaker that arranges marriages between Oracle clients and server processes
is called the Oracle Net Listener. The Listener ???listens??? for incoming connection
requests for one or more instances. The Listener is not part of the Oracle instance??”
it directs connection requests to the instance. The Listener is started and stopped
independently of the instance. If the Listener is down and the instance is up, clients
accessing the database over a network cannot find the instance because there is no
Listener to guide them. If the Listener is up and the instance is down, there is
nowhere to send clients.
The Listener??™s function is relatively simple:
1.
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