{
  "topology": {
    "leaves": ["leaf-a", "leaf-b"],
    "spines": ["spine-1", "spine-2"],
    "equal_cost_uplinks_per_leaf": 2
  },
  "ecmp": {"flow_count": 16},
  "incast": {
    "packet_bytes": 1500,
    "packets_per_sender": 32,
    "receiver_egress_bps": 1000000000,
    "sender_counts": [1, 8]
  }
}