Comparative Study on Rerouting Performance between OSPF and IS-IS Based on Hierarchical LAN Model

To meet the increasing demand for network availability, this paper compares OSPF and IS-IS link-state routing protocols through structured experiments in a hierarchical enterprise LAN simulated on EVE-NG. A three-layer topology was deployed, with redundant paths and controlled link and device failures. Key metrics such as interruption recovery time, neighbour failure detection, flooding time, and service quality were evaluated. Results indicate that IS-IS has faster response in neighbour detection and flooding, while OSPF performs more consistently in path control. These findings provide guidance for protocol selection in enterprise environments.