Recently, the bandwidth of networks has been increasing and the use of 100 Gigabit Ethernet is starting to be widely spread. One of the largest problem that we face to use 100 Gbps communications is a Bandwidth-Delay Product (BDP) problem. According to RFC7323, the maximum value of window size, or the BDP per TCP stream, must be less than 1 gigabytes. In long-distance fat-pipe networks, TCP cannot transmit sufficient amount of segments for the capacity of the link. In this study, we propose to modify the TCP stack implementation in end points for improving performance of single TCP stream. We evaluate our proposals on 40 Gbps networks with the very long latency and real 100 Gbps networks between Japan and the United States. We achieved data transfer for 1000 seconds by using single TCP communication at 62.67 Gbps on 100 Gbps networks. Our proposals are essential for 100 Gbps end-to-end communications.