SYSE.40:4.3 - Construct admission and bounded waiting

Admit work only under the selected resource and concurrency limits. Bound queues or waiting by the conditions that preserve task usefulness, including deadlines and cancellation behavior. Account for the resources consumed merely by holding or rejecting a request.

Separate workload or user classes where their coupling would violate the protected use. Reserve or independently provide control, health observation and recovery capacity when that is necessary. Verify that a shared downstream resource does not invalidate the apparent isolation.

Expose a useful response when work cannot be admitted. Give the user enough information to distinguish a refused attempt from one that may already have effects. A retry indication must reflect the qualified path, not encourage an immediate synchronized retry storm.