Which three statements about the route preference of IS-IS are true? (Choose three.)
A.
An L1 path is preferred over an L2 path.
B.
An L2 path is preferred over an L1 path.
C.
Within each level, a path that supports optional metrics is preferred over a path that supports
only the default metric.
D.
Within each level of metric support, the path with the lowest metric is preferred.
E.
The Cisco IS-IS implementation usually performs equal cost path load balancing on up to eight
paths.
F.
Both L1 and L2 routes will be installed in the routing table at the same time.
Given multiple possible routes to a particular destination, an L1 path is preferred over an L2 path.
Within each level, a path that supports the optional metrics is preferred over a path that supports
only the default metric. (Again, Cisco supports only the default metric, so the second order of
preference is not relevant to Cisco routers.) Within each level of metric support, the path with the
lowest metric is preferred. If multiple equal-cost, equal-level paths are found by the Decision
process, they are all entered into the route table. The Cisco IS-IS implementation usually performs
equal-cost load balancing on up to six paths.
Reference: http://www.realccielab.org/operation-of-integrated-is-is.html