The rapid development of cloud computing and big data has led to containers becoming the top choice for application deployment platforms due to their lightweight and flexible nature. Deploying, maintaining, and scaling containerized applications across dispersed environments has never been easier than with Kubernetes, a top container orchestration platform. Central to Kubernetes' functionality is its networking model, which connects containerized workloads seamlessly. This study explores Kubernetes network performance, emphasizing the role of Container Network Interfaces (CNIs) like Cilium, Flannel, Calico, and Antrea. Each CNI plugin is analyzed based on its architecture, functionality, and suitability for various application scenarios, highlighting trade-offs between simplicity, security, throughput, and scalability. Additionally, system tuning profiles and Kubernetes' default networking solutions are discussed to optimize communication between containers. The findings provide insights into selecting and configuring CNIs to enhance the performance, reliability, and security of Kubernetes clusters, offering guidance for deploying modern, network-intensive applications.