Flow-level and efficient traffic engineering in conventional routing systems

Abstract

Existing solutions of flow-level traffic engineering (TE) usually depend on the deployment of SDN or MPLS. In this paper, we design a flow-level and efficient TE scheme based on the conventional hop-by-hop routing protocol, i.e., OSPF. Motivated by the analysis and modeling on the real Internet traffic, we propose to detect and schedule a few large flows in real-time. The rerouting paths for large flows are computed in a centralized server and are distributed through extended OSPF. A few ACL entries are used for flow-level forwarding. We formalize the link weight assignment-based large flow scheduling problem and prove the problem is NP-hard. We propose to precompute several candidate paths to reduce decision computation overhead and path stretch. We develop an algorithm with performance bounds to allocate large flows to paths, and two algorithms to reduce extra LSA number for different system designs. Experiment results show our scheme can reroute large flows within 0.5 s. Simulation results show our scheme gets congestion metric values (i.e., performance ratios) 10% worse than the optimal for source and destination addresses-based flows. Our optimization mechanisms reduce the extra LSA number and computation time by 87% and 83% respectively for our scheme with pre-computed paths.