What is Port Address Translation (PAT)?
Port Address Translation (PAT) is a specific type of Network Address Translation (NAT) technique which is used in computer networking , PAT is commonly implemented in routers to allow multiple devices within a private network to share a single public IP address due to which it is sometime referred as NAT Overload. the main task of Port Address Translation (PAT) is to map multiple private IP addresses to a single public IP address by using unique port numbers ,when communication session is initiated by a device in the private network it is assigned with a unique port number which get combined with the private IP address to create a unique identifier for that specific communication session.
Advanced NAT Techniques: Port Address Translation (PAT)
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/