IOCP (Input/output Completion Port) performs various asynchronous input/output operations in Windows NT versions of 3.5 and later, AIX and also on Solaris 10 as well as later, simultaneously. This IOCP is created as well as related to several sockets or file handles. When the services of input/output are asked for on an object, a message to IOCP indicates about the completion. This completion of I/O services is not notified about the process requesting for I/O services; however, in fact it checks the port message queue of I/O completion to inform about its I/O request status. The IOCP knows how to manage various threads along with their concurrency in the world of computers.