A university is rebuilding a three-tier campus with 40 closets, VLANs confined to each closet, dual-homed access switches, and a mandate for no STP-blocked uplinks with subsecond failover using ECMP. Which loop-free campus topology best meets these routed-access goals?
Select an answer to reveal the explanation.
Short Explanation
You've got closet-local VLANs and dual links begging for routing, not spanning tree. Routed access turns both uplinks active with ECMP and kills STP loops for good, like swapping a detour for two open highways.
Full Explanation
Routed access is correct because placing Layer 3 on the closet with point-to-point uplinks terminates each VLAN locally, so no loop requires STP blocking and both dual-homed uplinks forward simultaneously via OSPF or EIGRP equal-cost paths for subsecond convergence while keeping broadcast domains and failure scope confined across 40 closets. A dual-homed multichassis EtherChannel design to a distribution pair is widely deployed for active-active forwarding without STP-blocked ports and with fast link failover, but it remains switched rather than routed and balances by EtherChannel hashing rather than installing multiple routed next hops, so it misses the ECMP routed-access mandate. A dual-homed routed design using hot-standby gateway redundancy is also standard for resilient localized VLANs with fast gateway failover, yet standby semantics keep one path idle for return traffic and do not load-share like ECMP, violating the active-active ECMP requirement. A dual-homed ECMP design with centralized gateways for seamless roaming retains routing and convergence advantages and is common for mobility, but centralizing gateways stretches the Layer 2 domain beyond the closet, breaking confined failure isolation and reintroducing flooding risk. Exam caveat is that EtherChannel load balancing and standby gateways can sound like ECMP, but only multiple equal-cost Layer 3 next hops qualify. Practically confirm with show ip route for dual equal-cost successors from each closet and show vlan confirming closet VLANs appear nowhere upstream.