Every request first reaches the nearest edge node (green ring = free capacity, amber/red = saturated). If the node has a free processing slot it answers locally — a short round trip. If not (or the node has failed), the request is relayed on to the central cloud and back — two extra network hops plus a heavier compute step.
edge_ok = node.active < capacity && node.enabled
t_edge = 2·t_net_edge + t_compute_edge
t_cloud = 2·t_net_edge + 2·t_net_cloud·congestion
+ t_compute_cloud
Raise the request rate or drop the capacity and edge nodes saturate faster, pushing more amber (cloud) traffic and lifting average latency. Network congestion only stretches the cloud leg — edge trips stay cheap. Fail a node and its whole device sector routes to the cloud until it's restored.