Context: Network hardware, software and specifications, as well as the expertise of network management personnel are important in ensuring that data follows the most efficient route, and upstream connections work reliably. A tradeoff between cost and efficiency is possible.[citation needed]

Question: Is a tradeoff between efficiency and cost possible? 
Answer: A tradeoff between cost and efficiency is possible

Question: What sort of route does data follow? 
Answer: the most efficient route

Question: What trade-off is not possible?
Answer: Unanswerable

Question: What follows most inefficient route?
Answer: Unanswerable

Question: What works unreliably?
Answer: Unanswerable

Question: What ensures upstream connections are not reliable?
Answer: Unanswerable