A dynamic load balanced scheme for two stage switches

Due to its outstanding extensible performance, the load balanced two stage switches have received much attention recently in the switching technology academia. However, the problem that it may disturb the sequences of packets makes it not so applicable in practice. To solve this problem, we first discuss the fundamentals required for guaranteeing packets in order switching in this paper. Then, based on these fundamentals, it focuses on research on the transmission characteristics of internet traffic, and comes up with an interesting dynamic flowlet switching (DFS) algorithm. Different from earlier proposed schemes, which try to ensure that packets belonging to the same input and output pair are switched in order, DFS guarantees that packets belonging to the same flow, which are defined by TCP/IP protocol, are kept in order. The main idea behind DFS is that the flows arriving at the switches are first divided into flowlets according to their destined output port and transport layer parameters (such as packets delay intervals), then switches them at a flowlet level. We evaluate DFS by theoretical analysis and simulations. The theoretical results show that DFS can guarantee packet in order delivering, while the simulation results show that DFS can achieve a good delay and throughput performance compared to existing typical schemes.