Question: Two communication nodes 1 and 2 send files to another node 3. Files from1I and 2 require on the average R1 and R2 time units for transmission, respectively. Node 3 processes a file of node i (i = 1, 2) in an average of Pi time units and then requests another file from either node I or node 2 (the rule of choice is left unspecified). If λi is the throughput of node i in files sent per unit time, what is the region of all feasible throughput pairs (λ1, λ2) for this system?