1. a) How does a given process running on a server and using a single UDP socket to communicate with different, distant clients distinguish between those clients when receiving segments from them?

b. If a server process is using TCP sockets to exchange transport layer segments with 4 remote hosts using persistent connections how many sockets (including the listening socket) will the server process be running? How many TCP destination ports will be used by the 4 remote hosts? What four pieces of information are attached to the segments/datagrams so that TCP payloads can be properly sent bidirectionally through the virtual pipe between the clients and the server?

c. What did the reliable data transport (rdt) protocol have to guard against retransmitted packets?

d. What did the reliable data transport (rdt) protocol have to guard against lost packets (i.e. how did they determine that a packet had probably been lost)?