The collapsed-core topology is the simplest of the listed SAN architectures because it removes a separate switching tier. Hosts and storage systems connect to the same high-port-density director or core-class switches, so traffic does not traverse dedicated edge switches and additional inter-switch links before reaching the storage target. Cisco’s SAN topology guidance describes collapsed core as simple to architect and implement and straightforward to maintain and troubleshoot. Fewer switches, ISLs, and fabric hops reduce configuration dependencies, failure points, zoning-path complexity, and the number of devices that must be inspected during fault isolation. The design also uses ports efficiently because interfaces that would otherwise form an edge-to-core layer can connect end devices directly. This simplicity has a scaling boundary: as the number of hosts and storage ports grows, a core-edge design may provide better expansion and aggregation, and physically separate fabrics A and B are still required for high availability. A core-edge topology adds an edge tier and ISLs, improving large-scale expansion but increasing operational complexity. A mesh interconnect creates many switch-to-switch relationships and becomes difficult to scale and troubleshoot. Edge-core-edge introduces still more tiers and is appropriate only when scale or traffic-engineering requirements justify them. Because the question asks specifically for the topology characterized by uncomplicated architecture, implementation, maintenance, and troubleshooting—not maximum scale—the collapsed-core design is the exact match. Cisco MDS collapsed-core deployment guidance

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