Connection Manager
Just as dedicated server processes take up overhead, so do network connections. Each network connection uses up some of the bandwidth of the network. Oracle Connection Manager, which first became available with Oracle8 Enterprise Edition, can use a single network connection to provide three key benefits:
- Multiple network sessions
Connection Manager works in conjunction with Shared Servers to provide the ability to handle multiple network sessions. This multiplexing reduces overhead.
- Translation between two different network protocols
Connection Manager can also be used as a way to translate between different network protocols in a heterogeneous network. A client can be running one protocol to Connection Manager and another one from Connection Manager to the Oracle Server.
- Translation of network addresses
You can also use Connection Manager to handle network address translation (NAT). When a client connects to an Oracle listener, its connection is redirected to either a dedicated server process or a dispatcher. This server entity sends its address back to the client. If the server is inside a firewall, the internal address returned may not be accessible to the client. This problem can be overcome by having Connection Manager act as an intermediary.[2]
Connection Manager can also be used to filter TCP/IP communications based on the IP addresses of the source or the destination or on the database service name.
You can have multiple machines with Connection Manager running ...