A dark fiber cut isolates a city's primary and DR data centers that had only one DCI path. Which interconnect design response is required?
Select an answer to reveal the explanation.
Short Explanation
One dark fiber is a single point of "oops." DCI resilience means diverse redundant interconnect paths so a cut does not orphan the DR site.
Full Explanation
A single dark-fiber cut that isolates primary and DR halls shows that DCI needs redundant, diversely routed interconnect paths so the municipal interconnect survives a single fiber failure. Design response is path diversity and redundancy, not clever overlay tweaks on a solitary span. Replacing DCI with intra-fabric leaf-spine links stretched across cities without redundancy planning repeats the same risk. Disabling EVPN on both borders until the fiber is restored maximizes downtime. Converting all tenants to L2 stretch does not uniquely enable redundant circuits—L3 DCI can use redundant circuits too. Exam caveat: diversity must be true (separate conduits/paths), not two lambdas in one cut-prone cable labeled redundant. Operational check: map physical routes of city DCI circuits, add a second diverse path, fail one path in testing, and confirm overlay/underlay adjacency recovers over the surviving path without manual EVPN disablement. Prove conduit diversity with physical path audits; dual circuits in one trench do not satisfy the city DR interconnect requirement. Prove conduit diversity with physical path audits; dual circuits in one trench do not satisfy the city DR interconnect requirement.