A Dynamic QoS Negotiation Mechanism Between Wired and Wireless SDN Domains

Flows in software defined networking (SDN) can pass through multiple domains having separate controllers. A domain is interpreted as part of the network topology under a SDN controller. This necessitates negotiation between various domains, to meet the QoS requirements of flows. These QoS negotiations may be static or dynamic. The SDN domains may be wired or wireless. Though, there have been efforts in the past to define inter-domain QoS negotiations for wired networks using SDN, to the best our knowledge, not much headway has been made when both wireless and wired domains are involved. In this paper, we consider a case where flows connect devices passing through a wired and a wireless domain having separate SDN controllers, and propose a novel QoS negotiation mechanism between them. First, we define a generic mechanism to map QoS parameters from one domain to the other. We then, define utilities for both the domains based on the QoS parameters of flows, and model our proposed mechanism as a mixed integer program. We observe that the problem is NP-complete, and propose a branch and bound-based algorithm to maximize the utility of the wireless domain, and evaluate the same for the wired part. Results indicate, as the resources provided to the flows in the wired domain varies dynamically, the wireless domain accordingly modifies the flows, satisfying their minimum/maximum QoS requirements under different scenarios. Conversely, this also means that resources in wired domain get adjusted, when wireless counterpart changes flow parameters based on wireless channel conditions. Further, the results reveal that smaller granularity of increment/decrement steps of QoS parameters satisfy flow requirements efficiently.