Assume that we know the bottleneck link along the path from the server to the client is the first link with rate bits/sec. suppose we send a pair of packets back to back from the server to the client, and there is no other traffic on this path. assume each packet of size l bits, and both links have the same propagation delay . a. what is the packet inter-arrival time at the destination? that is, how much time elapses from when the last bit of the first packet arrives until the last bit of the second packet arrives?