Evaluation of joint controller placement for latency and reliability-aware control plane

The separation of the forwarding and control planes in software-defined networking provides flexibility for network management. The Controller Placement Problem (CPP) is an important issue affecting network performance. This paper presents an evaluation of the Joint Latency and Reliability-Aware Controller Placement (LRCP) optimization model. LRCP provides network administrators with flexible choices to simultaneously achieve a trade-off between the switch-To-controller latency and the controller-To-controller latency, including the reliability aspect using alternative backup paths. Control plane latency (CPL) is used as the evaluation metric and it is defined as the sum of average switch-To-controller latency and the average inter-controller latency. For each optimal placement in the network, the control plane latency using the real latencies of the real network topology is computed. Results from the control plane latency metric show how the number and location of controllers influence the reliability of the network. In the event of a single link failure, the real CPL for LRCP placements is computed and assesses how good the LRCP placements are. The CPL metric is used to compare with other models using latency and reliability metrics.This publication is part of the Spanish I+D+i project TRAINER-A (ref. PID2020-118011GB-C21), funded by MCIN/AEI/10.13039/501100011033. This work has been also partially funded by the Spanish Ministry of Economy and Competitiveness, under contract TEC 2017-90034-C2-1-R (ALLIANCE).Peer ReviewedPostprint (author's final draft

Disaster-Resilient Control Plane Design and Mapping in Software-Defined Networks

Communication networks, such as core optical networks, heavily depend on their physical infrastructure, and hence they are vulnerable to man-made disasters, such as Electromagnetic Pulse (EMP) or Weapons of Mass Destruction (WMD) attacks, as well as to natural disasters. Large-scale disasters may cause huge data loss and connectivity disruption in these networks. As our dependence on network services increases, the need for novel survivability methods to mitigate the effects of disasters on communication networks becomes a major concern. Software-Defined Networking (SDN), by centralizing control logic and separating it from physical equipment, facilitates network programmability and opens up new ways to design disaster-resilient networks. On the other hand, to fully exploit the potential of SDN, along with data-plane survivability, we also need to design the control plane to be resilient enough to survive network failures caused by disasters. Several distributed SDN controller architectures have been proposed to mitigate the risks of overload and failure, but they are optimized for limited faults without addressing the extent of large-scale disaster failures. For disaster resiliency of the control plane, we propose to design it as a virtual network, which can be solved using Virtual Network Mapping techniques. We select appropriate mapping of the controllers over the physical network such that the connectivity among the controllers (controller-to-controller) and between the switches to the controllers (switch-to-controllers) is not compromised by physical infrastructure failures caused by disasters. We formally model this disaster-aware control-plane design and mapping problem, and demonstrate a significant reduction in the disruption of controller-to-controller and switch-to-controller communication channels using our approach.Comment: 6 page