How Does Port Address Translation (PAT) Work?

The functioning of Port Address Translation (PAT) is a well-structured process that involves the dynamic assignment of port numbers to facilitate efficient communication between devices within a private network and external servers. working of PAT can be divided into 3 steps lets have a closer look on these steps :

Step 1 :Port Assignment

When a device which is in a private network initiates the communication with an external server, PAT step in to assign a unique source port number to the communication session which is dynamically chosen from a pool of all the available ports. The uniqueness of each communication session is achieved by combining the private IP address of the device with the assigned source port number this combination of private IP address and source port number serves as a identifier for the session, while ensuring that multiple devices can share a single public IP address while maintaining the individual identity using different the port numbers assigned dynamically.

Step 2 : Translation Table (NAT table)

at the core of PAT’s operation a translation table is maintained which is also referred as NAT table , purpose of this table is to keep track of the intricate mapping between private IP addresses , corresponding private port numbers and the translated public IP address and port numbers , the translation table has become an important component for the router because it guides the accurate forwarding of incoming traffic.

When external entities respond to the communication initiated by devices within the private network, the router consults this table to determine the correct destination device based on the combination of the public IP address and port number and this is how the complete communication take place.

Step 3 :Dynamic Port Allocation

Port Address Translation (PAT) has the feature of dynamic port allocation To ensure efficient utilization of resources and at same time minimize the chances of port conflicts . When a device initiates an communication session PAT dynamically selects a port number from a pool of available ports , this dynamic allocation not only optimize the usage of the available resource at port but also allows large number of connection at a time . while devices within the private network engage in various communications PAT dynamically manages the allocation of unique port numbers, preventing conflicts and streamlining the flow of data.

Network Address Translation (NAT) is a networking technique used in routers to modify network address information in packet headers while in transit, Its main purpose is to enable the conservation of public IP addresses and facilitate communication between devices in private or local networks and the public Internet. now a days NAT is commonly implemented in home and corporate network environments for further to know about Network Address Translation refer to
https://www.w3wiki.org/network-address-translation-nat/