MPLS-based Reduction of Flow Table Entries in SDN Switches Supporting Multipath Transmission

TL;DR

This paper introduces an MPLS-based flow aggregation mechanism for SDN switches supporting multipath transmission, significantly reducing flow entries and controller-switch communication while improving network resource utilization.

Contribution

It presents a novel MPLS-based flow aggregation method that requires no new protocols and can be incrementally deployed in legacy SDN networks.

Findings

Flow entries reduced by up to 96% in core switches.

OpenFlow message exchanges decreased by approximately 98%.

Network traffic increased by about 32%.

Abstract

In the paper, a new mechanism for Software-Defined Networking (SDN) flow aggregation accompanied with multipath transmission is proposed. The aggregation results in a low number of flow entries in core switches. This type of scalability improvement of flow processing is obtained thanks to application of the procedure based on introduction of centrally managed MPLS label distribution performed by an SDN controller. Moreover, multipath transmission improves network resource utilization. The proposed mechanism does not involve definition of new protocols. It neither needs application of legacy signalling protocols. Only simple modifications of the existing solutions, assured by flexibility of OpenFlow, are necessary. Additionally, the mechanism significantly reduces communication between the controller and switches, thus enabling a fine-grained flow-level control. Furthermore, the proposed solution can be incrementally deployed in legacy networks. The simulations show that a number of flow entries in core switches can be reduced as much as of 96%, while the overall network traffic is increased by about 32\%. Moreover, the number of OpenFlow messages is reduced by about 98%.