What topology does a routed ToR design aim to reduce fault domains in?

• A. L2 fault domain.
• B. L3 fault domain.
• C. Spanning tree domains.
• D. IP address planning.

Answer: (A)

Routed ToR places a layer-3 boundary at each rack, so Layer 2 is no longer a single, fabric-wide domain. Traffic between racks is routed, not bridged, which contains L2 broadcasts and failures to the local rack’s domain. As a result, the size of Layer 2 fault domains is reduced, meaning a problem in one rack’s L2 network won’t cascade across the whole data center. The other options don’t fit as well: IP address planning isn’t a fault domain concept, and Spanning Tree domains relate to L2 flooding (which routed ToR designs avoid across the whole fabric).