SDN-based pro-active flow installation mechanism for delay reduction in IoT

In Software Defined Networks (SDN) a Controller installs forwarding rules or queries the status of network devices through a separate control channel using the OpenFlow protocol. Such queries may ask for instantaneous metrics, like port status, packet error rate, or transmitted packets. In turn, the Controller uses these metrics, or context, to condition forwarding rules. As network conditions change over time, forwarding rules are set to expire if not used (or matched) during a configurable idle timeout. Consequently, they are erased from the flow table, forcing a query to the Controller every time a packet for which there is no forwarding rule arrives at the network device. This work presents experimental results showing the delay increase produced by timing out forwarding rules of periodic flows, such as the generated by sensors in IoT deployments. Furthermore, it proposes and experimentally evaluates a pro-active forwarding rule installation mechanism able to reduce such delay by 90%, easing the implementation of context-aware forwarding strategies for IoT.