What are two best practices when designing a campus Layer 3 infrastructure? (Choose two.)

While configuring passive-interface on nontransit links is a good practice for security and resource saving, it's generally considered less impactful on the overall design of a high-performance campus Layer 3 infrastructure compared to route summarization or ECMP optimization.

Implementing security features like firewalls or extensive ACLs at the core layer goes against the principle of a lean, fast-forwarding core, as it introduces latency and reduces throughput; security is typically implemented at the distribution/aggregation layer or edge.

Route summarization from the aggregation layer toward the core layer significantly reduces the number of routes in the core routing tables. This improves routing stability, reduces memory consumption, and speeds up convergence in the event of topology changes.

Tuning Cisco Express Forwarding (CEF) load balancing hash for Equal-Cost Multi-Path (ECMP) routing ensures that traffic is distributed efficiently and evenly across multiple parallel paths. This prevents issues like path polarization and maximizes the utilization of available bandwidth.

Summarizing from the access layer toward the aggregation layer is a valid route summarization best practice; however, if C is chosen, D represents a distinct critical design aspect related to traffic forwarding efficiency.