  In the "Bits Through Queues" paper, it was hypothesized that full feedback
always increases the capacity of first-in-first-out queues, except when the
service time distribution is memoryless. More recently, a non-explicit
sufficient condition under which feedback increases capacity was provided,
along with simple examples of service times meeting this condition. While this
condition yields examples where feedback is beneficial, it does not offer
explicit structural properties of such service times.
  In this paper, we show that full feedback increases capacity whenever the
service time has bounded support. This is achieved by investigating a
generalized notion of feedback, with full feedback and weak feedback as
particular cases.
