This article lists port numbers and their associated protocols that have experienced significant uptake.
Dynamic Source Routing (DSR) is a routing protocol for wireless mesh networks.
The even-numbered ports were not used, and this resulted in some even numbers in the well-known port number range being unassigned.
The Stream Control Transmission Protocol (SCTP) and the Datagram Congestion Control Protocol (DCCP) also use port numbers.
However, many unofficial uses of both well-known and registered port numbers occur in practice.
Similarly many of the official assignments refer to protocols that were never or are no longer in common use.
Course timings and content can also be customised as per requirements (charges extra).
Originally, port numbers were used by the Network Control Program (NCP) in the ARPANET for which two ports were required for half-duplex transmission.
Later, the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP) needed only one port for full-duplex, bidirectional traffic.
It associates various information with domain names assigned to each of the participating entities.
Most prominently, it translates more readily memorized domain names to the numerical IP addresses needed for locating and identifying computer services and devices with the underlying network protocols.