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* Description: Knowledge of network server port
* Compatiablity: RDBMS 11g, 12c
* Date: 03:23 PM EST, 05/18/2017
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<1> Network Server Port:	 
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     |__ o. Specific port numbers are often used to identify specific services. 
            Port numbers are part of the addressing information used to identify the senders and receivers of messages. 
            Port numbers are associated with TCP/IP network connections. They allow different applications on the same computer to share network resources simultaneously. 
            Home network routers and computer software work with these ports and sometimes support configuring port number settings.

         o. Do not confuse this kind of port with the physical ports that network devices have for plugging in cables.

         o. For example, you are visiting a website, QQ chating with your friend, and send/receiving emails simutenously on one machine, and then when a data packet arrives.
            How can you tell this data packet should be read by which process? How to tell what is the content about, chating, email, or a HTML file?
            Therefore, transport layer of TCP/IP model defines - within a data packet, there should be a parameter indicating which process is ought to receive it. The parameter
            is "Port". So, when the data packet reaches target server network interface card, which processs should be assigned to.