IS-IS (Intermediate System to Intermediate System)

IS-IS (Intermediate System to Intermediate System) is a routing protocol used by large networks to determine the best path for data to travel across multiple connected devices. It helps network devices, called routers, exchange information about the network's layout, ensuring data efficiently reaches its destination. Think of it as a navigation system for data packets, constantly updating routes based on network changes to maintain reliable communication. Used mainly by service providers and large enterprises, IS-IS supports complex, scalable network architectures and ensures high-speed, accurate data delivery.