Models and algorithms for centralized control planes to optimize control traffic overhead

Carrier Ethernet has rapidly advanced to become an important technology in metro transport. However, the overlapping of control plane and data plane in contemporary Carrier Ethernet (CE) networks leads to complex and unmanageable networks. CE networks that use packet technologies ought to be more manageable, scalable and robust. Recently proposed network architecture, Omnipresent Ethernet (OE) recommends that the control and management plane in CE networks be decoupled from the forwarding and routing plane to overcome the problem mentioned earlier. In view of this, we investigate the possibility of a centralized control plane from OE perspective. A centralized control plane is a networking paradigm that abstracts and centralizes the control information of the network from the underlying distributed data-forwarding infrastructure. In this paper, we have focused on engineering and architectural issues related to the design of a centralized control plane for the networks built on OE Networking paradigm. Furthermore, the problem of control traffic overhead in managed networks is analyzed using an appropriate simulation model. A scheme to divide the network into smaller sub-networks is proposed so that the total control traffic is always below some threshold. An Integer Linear Program (ILP) for the controllers' placement in the partitioned network is presented. The ILP attempts to minimize the total control traffic, the total controllers' implementation cost and the overall response time in the network. Since the ILP solves the problem optimally for networks with a limited number of nodes, a heuristic approach is developed and presented for larger and real-time service-provider networks.