3. (MAC) Consider a multi-access link where there are 4 nodes sharing the link's bandwidth, B bps. During the day, users of the 4 nodes are all working and need to send data. During the night, only the users on 1 node remain. (a) Suppose this multi-access link runs a TDMA protocol where a cycle is equally divided into 4 slots. Each slot is allocated to each of the 4 nodes. How long does it take for all nodes to finish sending T bits each at the same time during the day? How long does it take for the working node to finish sending T bits during the night? (4%) (b) Suppose this multi-access link runs a Token Ring protocol. How long does it take for all nodes to finish sending T bits of data each at the same time during the day? How long does it take for the working node to finish sending T bits during the night? (4%) (c) Suppose this multi-access link runs a CSMA/CD protocol. How long does it take for each node to finish sending T bits at the same during the day? How long does it take for the working node to finish sending T bits during the night? In case of collisions, suppose the amount of extra bits to transmit due to collision is T' per node. (4%) (d) Can you identify a protocol that performs well both during the day and the night and which protocol is it? (4%)