Now-a-days, efforts have been made in the research of transmission control protocols to improve the performance of the flow control mechanism. Internet communication and services daily increase the variety and quantity of their capacity and needs. Therefore the flow control mechanism will have to consider valuable for traffic control, especially on high-speed networks. Initially there are some challenges, for instance, loss of packet, processing capacity, performance, buffer overflows and deadlocks with which daily traffic is confronted. This paper analyzes and reviewed the strengths and weaknesses of the different flow control mechanisms used in TCP. To overcome the weaknesses of these flow controls, we suggest a priority retransmission mechanism. Here we have priority on the Negative Acknowledgment (NACK), we resend the package on the basis of the minimum sequence number of the NACK. In buffer of priority retransmission Automatic Repeat request (ARQ) mechanism, the packet is released to the communication link in a First in First out (FIFO) manner. That is why the priority retransmission ARQ gives the optimum performance
Prioritized Retransmission: A TCP Flow Control Mechanism