STUDY OF RELIABILITY AND FAULT TOLERANCE MANAGEMENT IN INFORMATION AND COMMUNICATION NETWORKS: MODELING AND TESTING OF DEFAULT GATEWAY REDUNDANCY PROTOCOLS

The article is devoted to researching reliability and fault tolerance management mechanisms in infocommunication networks, focusing on modeling and testing of gateway redundancy protocols. The work considers the VRRP (Virtual Router Redundancy Protocol) and GLBP (Gateway Load Balancing Protocol) protocols, which ensure continuous network operation in the event of a primary gateway failure. The purpose of the study is to compare these protocols using the virtual environments EVE-NG and Containerlab, as well as to test them on physical and virtual devices. The article analyzes the characteristics and mechanisms of both protocols, the software implementation, and the configuration of the protocols on Cisco devices in emulation environments and tests their effectiveness in the face of gateway failures. The results showed that VRRP provides minimal packet loss and fast switching between master and backup gateways, making it optimal for networks with high requirements for connection continuity. Instead, GLBP provides load balancing between gateways but is accompanied by higher packet loss and longer switching times, which limits its use in critical networks. In particular, testing in virtual environments has shown that when using virtualized links and resources, VRRP delays and packet loss are significantly lower than GLBP. Therefore, testing in virtual environments is useful for preliminary analysis of configurations, although testing on real devices is necessary to determine the protocols' effectiveness accurately. We also consider the possibilities of using GLBP in large networks to provide not only redundancy but also optimize traffic balancing. Based on the results obtained, we formulate suggestions for future research, including optimizing switching times between gateways and developing hybrid solutions that combine the advantages of both protocols, VRRP and GLBP, to improve traffic management and redundancy and create more flexible and fault-tolerant infrastructures.