Minimum weight controller tree design in SDN

• Published in: Computer networks (Amsterdam, Netherlands : 1999) Vol. 165; p. 106949
• Main Authors: Yang, Ze, Yeung, Kwan L.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 24-12-2019; Elsevier Sequoia S.A
• Subjects: Algorithms; Communication; Control systems design; Controllers; Heuristic methods; Integer programming; Linear programming; Local fast reroute; Minimum weight; Minimum weight controller tree; Minimum weight design; Network survivability; Software-defined networking; Switches; Network survivability; Local fast reroute; Minimum weight controller tree
• ISSN: 1389-1286; 1872-7069
• DOI: 10.1016/j.comnet.2019.106949

We consider an SDN based network with a single controller communicating with all the switches using a controller tree. When a switch is protected from the failure of its parent node using local fast reroute, its weight is 0; otherwise, its weight is the number of switches will be disconnected from the controller. In this paper, we study the problem of finding the minimum weight controller tree (mwCT), where the tree weight is the sum of all switch weights. Four original contributions are made. First, a new sibling protection mechanism is designed to maximize the number of protected switches. Second, we prove that the mwCT problem is NP-hard. Third, the first Integer Linear Programming (ILP) for solving the mwCT problem is formulated. Finally, an efficient heuristic algorithm for controller tree construction, called Distance-Degree Ordered Tree (DDOT), is proposed. Unlike ILP, DDOT minimizes not only the tree weight but also the average controller-switch distance.