I guess you must be needing a buffer at the router in order to handle extra incoming traffic
Buffer must be min = 44.56 - 39.53 = 5.03 Mb
ip rate must be equal to o/p rate or else you need buffer to compensate extra i/p
in your case ip to router is 44.56Mb in 1s but your router can process and output only 39.53Mb only so extra 5.03Mb you need to store somewhere to process later for o/p or else it gets dropped