A township sees unequal ECMP utilization because underlay metrics were set inconsistently across leaf-spine paths. What does that symptom highlight?
Select an answer to reveal the explanation.
Short Explanation
ECMP is picky—it only load-shares paths that cost the same. Skew the metrics and some spine links become wallflowers while others sweat. Fix the costs if you want the Clos to share fairly.
Full Explanation
Fabric ECMP depends on equal-cost underlay paths; mismatched metrics across leaf-spine paths prevent equal multipath membership and cause unequal utilization in the township Clos. ECMP does not ignore metrics and always spray round-robin regardless of cost. Unequal metrics are not a reason to fall back to STP for multipath. BGP can ECMP on Junos when costs and multipath configuration align; metrics are relevant. Exam caveat: Normalize interface costs/metrics so intended spines share equally. Operational check: Compare path costs to each spine and fix mismatches until ECMP members and utilization align. In civic data-center operations, record the expected CLI or collector evidence for this concept so the next on-call engineer can validate fabric behavior without re-deriving the design under incident pressure. In civic data-center operations, record the expected CLI or collector evidence for this concept so the next on-call engineer can validate fabric behavior without re-deriving the design under incident pressure. In civic data-center operations, record the expected CLI or collector evidence for this concept so the next on-call engineer can validate fabric behavior without re-deriving the design under incident pressure.