6) (21 points) Consider the network in Figure 3 consisting of a 100 Mbps Ethernet, an Ethernet switch (without cut-through switching functionality), and a 10 Mbps Ethernet. Suppose that A wants to send a large number of 5,000 bit packets to B. (The 5,000 bits include the data and all Ethernet header, trailer and preamble fields.) Suppose this is the only active session on the network. Assume propagation delays and processing times are negligible, and acknowledgements are instantaneously returned from B to A 10 Mbps Ethernet Switch 100 Mbps a) Find the round-trip time, d. (Recall that the round-trip time is the length of time from when a host begins to transmit a packet until when the host receives an acknowledgement of the packet.)