Which configuration example sets per-flow equal-cost multipath (ECMP) load balancing for OSPF routes?

The configuration that sets per-flow equal-cost multipath (ECMP) load balancing for OSPF routes provides a specific way to manage how multiple paths are utilized for traffic flowing through a network. In this context, the correct answer incorporates the necessary components of the routing-options and policy-options structures, including the forwarding table and export statement.

In option C, the configuration begins with the routing-options section defining the forwarding table and an export statement for ECMP. This is crucial because the forwarding table is responsible for determining how packets are routed once they are in transit. By specifying 'export ECMP' within the forwarding table, it ensures that multiple equal-cost paths are taken into consideration for route selection.

Furthermore, the inclusion of the policy-statement with a term that matches routes from the OSPF protocol and indicates a load-balance directive ensures that the traffic is distributed evenly across the equal-cost paths. The 'load-balance per-packet' directive enhances this by specifying how packets should be balanced over the possible paths, allowing for optimal use of available bandwidth and improving overall network performance.

The focus on 'per-packet' load balancing, as specified, applies the load balancing mechanism on an individual packet level rather than at the flow level, providing effective