Parallel transmission is one of the popular techniques to realize huge bandwidth hetween two network nodes. However, in parallel transmission, many packet order inversions will be occurred when the delay difference among the routes is large, and TCP throughput will he drastically decreased under such a circumstance. In this paper, a TCP over SCTP (Stream Control Transmission Protocol) parallel transmission system is proposed to realize large TCP throughput over parallel transmission. In proposal, TCP is used in order to achieve end-to-end communication, SCTP plays a role to defeat packet inversion. Each TCP packet is encapsulated into SCTP packet at Gateway node which is located on edge of a parallel transmission section. In this paper, the proposed system is implemented on the software switch to evaluate parallel transmission. A parallel route selection algorithm is also proposed and evaluated delay difference characteristics.