## 1 Introduction  
Corporate networks require a stable connection with internet services and remote branches. Organizations strive to minimize network downtime through link-failover mechanisms. However, a significant limitation of these mechanisms is the idle state of backup links when the primary link remains operational for extended periods, leading to unnecessary costs for unused resources. Additionally, organizations managing both branch-to-branch communication and internet traffic face challenges in handling these traffic types simultaneously. For security reasons, some organizations mandate that data traffic must traverse an overlay network, while internet traffic uses an underlay network. Moreover, organizations seek the flexibility to choose optimal paths for network traffic to enhance performance. Network engineers often struggle to select the most appropriate routing protocol without a thorough understanding of the strengths and limitations of available options. This knowledge is essential for improving routing infrastructure and ensuring effective traffic distribution. Therefore, a comprehensive solution is needed that efficiently utilizes backup links, manages dual traffic types, secures and optimizes routing paths, and equipsnetwork engineers with the necessary insights to choose the best routing protocols for superior network performance. This study aims to provide valuable insights for researchers and network engineers on the performance of Enhanced Interior Gateway Routing Protocol (EIGRP) and Open Shortest Path First (OSPF) when integrated with Border Gateway Protocol (BGP), particularly in the contexts of load sharing and link-failover strategies. To conduct a thorough evaluation, this work employs simulation tools like Graphical Network Simulator-3 (GNS3) for network topology simulation, VMware for virtualization, and Wireshark and Iperf3 for detailed network analysis. These tools allow us to create realistic network scenarios and assess critical performance metrics such as packet loss, convergence time, network jitter, and delay. As networks continue to evolve to support new technologies, a robust routing infrastructure becomes increasingly essential. This study contributes to the understanding of how routing protocols perform in modern network environments. By combining BGP, which plays a key role in connecting autonomous systems, with widely used interior gateway protocols like OSPF and EIGRP, our research offers a comprehensive view of routing protocol efficiency in practical settings. This work aims to identify the strengths and weaknesses of OSPF and EIGRP in scenarios involving load sharing and link failures, thereby evaluating their suitability for various networking contexts. Including Internet Protocol version 6 (IPv6) in the analysis ensures that the findings align with the industry's transition to the latest version of the Internet Protocol. Advanced simulation tools, such as GNS3, facilitate this investigation by enabling the construction of realistic network environments for in-depth analysis. By simulating real-world conditions, we can observe how different routing protocols perform in dynamic and changing network environments. The ultimate goal is to extract actionable insights from the collected data, providing researchers and network engineers with the knowledge needed to make informed decisions about selecting and implementing routing protocols in contemporary networking scenarios. This research aims to enhance network performance, flexibility, and scalability by understanding the intricate dynamics of OSPF and EIGRP in conjunction with BGP, particularly in the context of IPv6. The expected outcomes will serve as a valuable resource for making informed choices, ensuring that routing protocols effectively meet the evolving demands of modern network architectures.