Towards the optimal orchestration of service function chains to enable ultra-reliable low latency communication in an NFV-enabled network
The growing utilization of Ultra-Reliable Low Latency Communication (URLLC) in 5G/6G networks, the Internet of Things (IoT), and fixed-line networks has considerably increased the significance of reliability and latency requirements within the telecommunications sector. Communication Service Providers (CSPs) encounter emerging challenges in optimizing reliability and latency to support Ultra-Reliable Low Latency Applications (URLLA). These applications include autonomous driving, remote surgery, tele-operated driving, and virtual reality. Simultaneously enhancing both reliability and latency poses a significant challenge, as enhancing reliability may potentially lead to increased latency. Furthermore, the limited availability of physical network resources increases the complexity of this endeavor.
Network Function Virtualization (NFV) is a promising technology that has the potential to overcome some of the limitations associated with conventional network architectures, thereby enabling URLLC. The integration of NFV with Software-Defined Networking (SDN) represents a revolutionary technological advancement that has the capacity to fundamentally transform existing network designs. NFV is the deployment of network functions as virtual software running on standard hardware. By decoupling network functions from dedicated hardware in NFV, greater network performance and management flexibility can be achieved. NFV relies heavily on Service Function Chain (SFC) deployment to realize network services. SFC refers to delivering a network service to a customer, which requires that different network functions be concatenated in a specific order. See Chapter 1 for more information. Although NFV is a promising technology for providing elastic network services, it is important to note that there are several concerns related to its reliability and service quality. This creates a new research problem known as the SFC deployment problem. This problem is concerned with chaining Virtual Network Functions (VNFs) while meeting SFC requirements such as latency, reliability, physical resource consumption, power consumption, etc. CSPs must have optimal and efficient SFC embedding techniques for embedding SFC requests to enable URLLC. Chapter 1 provides more information.The goal of this study is to address URLLC in an NFV-enabled network. After analyzing state-of-the-art studies in the field of NFV (see Chapter 2), we identified a crucial research obstacle. Consequently, we defined our goal to simultaneously optimize reliability and latency in the SFC deployment phase. We offer a novel and efficient SFC embedding technique that aims to enhance the reliability and latency of URLLA simultaneously. Mathematically, we formulate the SFC deployment problem as an integer-linear-programming optimization model to obtain exact numerical solutions. More information can be found in Chapter 4. In our optimization model, we propose an adjustable priority coefficient factor and flow prioritization to reserve a portion of physical network resources (bandwidth, RAM memory, and CPU) exclusively for embedding URLLA to significantly optimize their deployment paths. Since obtaining exact numerical solutions is time-consuming, we provide a set of heuristics and relaxed versions for addressing the scalability issue, reducing execution time, and producing results that are close to optimal for large-scale network topologies. Chapter 5 provides further information about heuristic approaches. In this study, we explore both static and dynamic service function chaining; further information is provided in Chapter 1. The performance evaluations reveal that our proposed algorithms considerably outperform the existing approaches in terms of end-to-end delay, reliability, bandwidth consumption, and SFC acceptance rate. See Chapter 6 for more details.