Which configuration example accomplishes per-flow load balancing for all routes on Router-1?

The configuration example that achieves per-flow load balancing for all routes on Router-1 is correct because it utilizes the appropriate set of commands to enable this functionality across the entire routing table.

By including routing-options { forwarding-table { export ECMP; } }, this configuration sets up the routing table to consider Equal-Cost Multi-Path (ECMP) routes. ECMP allows multiple paths to be used for forwarding packets, which in turn facilitates load balancing.

The critical part here is the configuration of the policy statement. By using policy-options { policy-statement ECMP { term first { then { load-balance per-packet; } } }}, the statement explicitly instructs the router to distribute packets across the available paths on a per-packet basis. This means that different packets belonging to the same flow may take different paths based on the load balancing algorithm applied.

The focus on making this per-packet type of load balancing permits more granular traffic distribution compared to other methods, contributing effectively to optimized bandwidth utilization and overall performance.

Thus, this configuration demonstrates a comprehensive approach to enable per-flow load balancing for all routes, ensuring that all potential paths are considered for outgoing traffic.