Managing path diversity in layer 2 critical networks by using OpenFlow

Critical environments demand redundant networks to achieve high availability. Also, many industrial applications have stringent latency requirements that must be met by the Ethernet mesh networks in which they are supported. However, redundant resources are usually used as backup solutions, being underutilized most of the time. This paper analyzes the relation between the network meshing and load balancing with the latency. As a representative example, it is shown that network management in modern substation automation systems can be improved through the Software-Defined Networking (SDN) paradigm. In contrast to spanning tree-based networks, this paper describes how the OpenFlow technology is used to control Local Area Networks (LANs) to make the most of redundant topologies. Thus, an external controller provides flow-aware load balancing that impacts directly latency reduction, meeting the IEC 61850 requirements. Through emulation it is studied how data flows in IEC 61850-based substation communication systems are balanced as required.