Which layer determines the effective idle timeout for PowerShell remoting sessions?

When deploying a low‑traffic administrative workload on a cloud VM, the goal is to keep the PowerShell remoting session alive only long enough to handle sporadic commands while minimizing host resource usage and associated costs.

Both the client and the server expose idle‑timeout settings: the client can pass New‑PSSessionOption -IdleTimeout and the server exposes IdleTimeoutMs in the WSMan session configuration. In Windows PowerShell 5.1 and PowerShell 7.x these settings coexist, yet the documented precedence is unclear, and the interaction may differ between HTTP and HTTPS transports.

Another concern is whether terminating a session due to an idle timeout releases the underlying host resources immediately, or if there is a lag caused by runspace garbage collection or the WinRM service’s internal cleanup.

1. Which layer—client or server—ultimately enforces the idle timeout when both are configured?
2. Does the session termination trigger immediate deallocation of host resources, or is there a measurable delay?
3. Can we rely on idle timeout alone to lower cloud consumption costs for a low‑traffic workload, or is external orchestration required?