By default, if IS-IS is enabled on all routers, and this is an IPv6 network, what path is taken?

IS-IS, by default, determines the best path to a destination based on the shortest path first algorithm using link costs (metrics). In the absence of explicit equal-cost or unequal-cost load balancing configurations, IS-IS will always select and use the single path that has the lowest overall cumulative metric to the destination, which in this case is designated as Path 1.

Path 2 would only be chosen if it had a lower cumulative metric than Path 1, which contradicts the given correct answer that specifies Path 1.

Unequal-cost load balancing is not a default behavior in IS-IS; it requires specific configuration.

Equal-cost load balancing would only occur if Path 1 and Path 2 had identical cumulative metrics, and even then, the default behavior often involves load balancing, but the answer suggests a single best path.