## 2 Related Work
The existing proposals for energy savings and how network management technologies could lead to undesired energy consequences, such as load balancing or link saturation problems, are evaluated. The conflicting nature of energy-saving and load-balancing objectives makes simultaneous optimization a challenge. In order to tackle this task, an energy-efficient and load-balanced online flow routing framework based on software-defined networking is proposed, followed by an optimization problem to balance energy savings and load. A route-updating algorithm that is flexible to changes in flow scheduling is also proposed. The experimental results demonstrate the superiority of the proposed algorithm over benchmarks in energy savings, load balancing, and reducing link congestion risks. In [15], the study examines how Boolean algebra concepts can be used to solve problems in operations research. This technique helps transform complex binary quadratic problems into simpler linear ones. In [16], the migration of a traditional corporate network to the SDN architecture is studied to demonstrate the advantages of an SDN network compared to a conventional network. For this purpose, a classic corporate network was simulated, and then the simulation was migrated to an SDN architecture. The network simulation was carried out using a virtual environment (MININET). By comparing the implementation process of these two networks, the simplicity of the SDN network implementation compared to the classic network was shown. In order to study the complexity of maintenance, two scenarios were used: the migration from one virtual local area network (VLAN) to two VLANs and the evolution of routing rules in both networks. In [17], in response to the slow but steady adoption of SDN architectures and the current solutions to manage them, this work proposes a new efficient SDN architecture based on a flat multi-controller multi-domain network that provides efficient load balancing in the network. Its performance was demonstrated and verified through simulations in a Mininet environment with Ryu controllers. In [18], the authors introduce a solution designed to improve load balancing in SDNs with multiple controllers, thereby enhancing network performance. It uses a greedy approach to migrate switches from overloaded controllers to underloaded ones based on deviations in controller loads from the average. This ensures each controller has a balanced load with minimal switch migrations. The algorithm's effectiveness is demonstrated through the analysis of time and space complexities, along with simulations and experimental studies showing superior performance in terms of switch migrations, response time, throughput, and delay compared to traditional methods. In [19], as data flows, industrial applications grow exponentially, achieving low-latency and reliable data transmission simultaneously poses a challenge. Time-sensitive software-defined networking (TSSDN) has emerged as a technology for combining the real-time network configuration capabilities from SDN with deterministic flow delivery from time-sensitive networking (TSN), which is ideal for industrial internet of things (IIoT) applications. In order to address this challenge, a frame replication and elimination for reliability (FRER) mechanism is proposed for TSSDN-based IIoT systems. However, FRER introduces stress on already limited network resources by creating redundant paths. In order to tackle this concern, an end-to-end delay-bound model and reliability model are proposed for analysis. An optimization problem is formulated to maximize overall system utility while meeting commercial flow transmission requirements and hardware resource constraints. Numerical simulations validate the effectiveness and performance superiority of the proposed approach over existing methods. Reference [20] explores the management of users across various segments within an SDN, aiming to minimize the latency among switches, controllers, and user access nodes.