Connections that died quietly every sixty seconds
The sockets are long-lived and mostly quiet. After roughly a minute of no traffic they stop working, and neither end logs an error — because neither end noticed. Something in the middle closed the connection.
An intermediary's idle timer counts any traffic, and a socket that is quiet is idle by that definition. Something has to keep it warm, and something separate has to notice when the peer is gone.
Outside every boundary: Load balancer (idle timeout 60s), No messages for 90s (a normal afternoon), Client, Socket server (FAILED: peer already gone), an empty slot for the shorter than any idle timeout, an empty slot for the what proves the peer is alive Connections: Client holds an open connection to Load balancer (step 1) Load balancer holds an open connection to Socket server (step 2) No messages for 90s controls Load balancer — counts as idle shorter than any idle timeout controls Load balancer — resets the timer (step 3) what proves the peer is alive controls Socket server — no reply, close it (step 4)