A Network Coding Approach to In-Band Control Traffic Sharing in Software Defined Networks
Fayaz Akhtar, Mubashir Husain Rehmani, Alan Davy · 2018
In-band southbound connectivity provides a cost-efficient way to share control traffic between the software-defined network controller and underlying forwarding devices; without having to worry about establishing and maintaining a separate transport network. However, the adoption of such a design also exposes the control plane traffic to non-negligible delay and losses; incurred from burdening a single transport network with an increased number of transmissions. These drawbacks can severely degrade network performance. For instance, when the requests in the form of control packets from switch-to-controller (or vice-versa) are dropped, the information may not get updated promptly and thus, the system would not behave as desired or in the worst case scenario can collapse altogether. To mitigate these constraints, in this paper, we propose the use of network coding which encourages information mixing as packets traverse the network. We show that network coding when applied to control plane traffic in an in-band design can help overcome losses due to congestion and link impairments. Evaluation results suggest that network coding aware in-band design can mitigate number of transmissions as well as total delay incurred by control packet losses.