Path selection
Load balancing
Typically, networks are configured with multiple paths to a remote network. When these paths are equal
or nearly equal, it makes sense to utilize all the available paths. Unlike Layer 2 forwarding, Layer 3
forwarding has the capability to load-balance between multiple paths. That is, the router can send frames
out multiple interfaces to reduce the amount of traffic sent to a single network connection. The key to this
feature is that the network paths must be of equal cost (or nearly equal for some protocols like EIGRP).
EIGRP uses a metric to compute the costs to a given network.