[Translation from mos] How does OracleGoldenGate allocate ports between the source transmission process and the target server/collector process?

[Translation from mos] How does OracleGoldenGate allocate ports between the source transmission process and the target server/collector process?
How Does Oracle GoldenGate allocate ports between the source transmission process and the target server/collector process?
Source:
How Does GoldenGate Allocates Ports between Source Extract Pump and Target Server/Collector? (Documentation ID 965270.1)


Applicable:
Oracle GoldenGate-Version 9.5.0.0 and later
Information in this document applies to any platform.
* ** Checked for relevance on 24-May-2012 ***


Solution:
Background:
Generally, OGG uses TCP/IP to move the OGG trail from the source to the target end.
The extraction process (usually called Extract Pump) reads the local trail file and sends data to the server process (collector) on the target host over the network)


The configuration is as follows:
The parameter file of the Extract Pump process contains the rmthost parameter, which is similar to the following:
RMTHOST , MGRPORT
Example: rmthost remoteserver, MGRPORT 7809
To control the port usage on the target host, the DYNAMICPORTLIST parameter of the manager process is usually used. This parameter limits the port range used by OGG.
For example:
PORT 7809
DYNAMICPORTLIST 8000-8010


How can OGG allocate ports between the source transmission process and the target server/collector process?


When the Extract Pump process uses the port number specified in the rmthost parameter (rmthost remoteserver, MGRPORT 7809) to start the link to the target end,
The manager process runs on the target host and listens to port 7809.
The target manager will start a collector and pass to the collector if configured the DYAMICPORTLIST range of ports.
If this is not configured random ports will be used.
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The target manager process returns to port 7809 for listening.
The Collector process tries to use each port in sequence (called TCP/IP BIND) until collector finds that a port can work.
The Collector process will contact Extract pump and instruct the Extract pump process to use this port for communication.


Note:
You can use the following command to check the port usage on the target end:
GGSCI> send mgr getportinfo.
Before OGG version 11, the manager Process searches for a port on the server rather than locating an available port on the server.