OpenFIow Based Flow Slice Load Balancing

Today's data center networks are designed using densely interconnected hosts in the data center.There are multiple paths between source host and destination server.Therefore,how to balance traffic is key issue with the fast growth of network applications.Although lots of load balancing methods have been proposed,the traditional approaches cannot fully satisfy the requirement of load balancing in data center networks.The main reason is the lack of efficient ways to obtain network traffic statistics from each network device.As a solution,the OpenFlow protocol enables monitoring traffic statistics by a centralized controller.However,existing solutions based on OpenFlow present a difficult dilemma between load balancing and packet reordering.To achieve a balance between load balancing and packet reordering,we propose an OpenFlow based flow slice load balancing algorithm.Through introducing the idea of differentiated service,the scheme classifies Internet flows into two categories:the aggressive and the normal,and applies different splitting granularities to the two classes of flows.This scheme improves the performance of load balancing and also reduces the number of reordering packets.Using the trace-driven simulations,we show that the proposed scheme gains over 50%improvement over previous schemes under the path delay estimation errors,and is a practical and efficient algorithm.

TCP-ACC： performance and analysis of an active congestion control algorithm for heterogeneous networks

Transmission control protocol （TCP） is a reli- able transport layer protocol widely used in the Internet over decades. However, the performances of existing TCP conges- tion control algorithms degrade severely in modern heteroge- neous networks with random packet losses, packet reordering and congestion. In this paper, we propose a novel TCP algo- rithm named TCP-ACC to handle all three challenges men- tioned above. It integrates 1） a real-time reorder metric for calculating the probabilities of unnecessary Fast Retransmit （FRetran） and Timeouts （TO）, 2） an improved RTT estima- tion algorithm giving more weights to packets that are sent （as opposed to received） more recently, and 3） an improved congestion control mechanism based on packet loss and re- order rate measurements. Theoretical analysis demonstrates the equilibrium throughput of TCP-ACC is much higher than traditional TCP, while maintaining good fairness with regard to other TCP algorithms in ideal network conditions. Ex- tensive experimental results using both network emulators and real network show that the algorithm achieves signifi- cant throughput improvement in heterogeneous networks as compared with other state-of-the-art algorithms.