The connection topology of the interconnection networks and the routing algorithm often dominate the system performance in MPCs. RDT has already been proved to be one of the best interconnection networks used in such systems. It supports smaller diameter and degree than most of others at the size of one thousand to tens of thousands nodes. The floating vector routing algorithm is very effective to transfer messages, which also shows good performance.In this paper, a descending vector routing algorithm is proposed. We also proposed a practical torus assignment named RDT(2,2,1)/α and the deadlock-free routing algorithm. RDT(2,2,1)/α mainly focuses on the MPC that has about one thousand nodes. With a simplified simulation and comparison, the results show that RDT(2,2,1)/α has a better performance at the size of one thousand nodes.