Explains how traffic reaches and moves between pods — Services (ClusterIP/NodePort/LoadBalancer), Ingress and controllers, cluster DNS, NetworkPolicy default-deny, and debugging selector mismatches or empty endpoints. Use this whenever the user asks why a Service has no endpoints, why a request 502s inside the cluster, how to expose an app externally, or how to write a NetworkPolicy. For readiness-driven endpoint removal use `kubernetes-operations`; for mTLS at L7 use `service-mesh`.
