2. KR, Ch. 6- P15 (slightly reworded with a modified figure). Consider the figure below where S1 and S2 are switches and RI is a router. Hosts A, B, C, and D belong to Subnet 1/2 (in this modification of Figure 6.33 of the text), while hosts E and F belong to Subnet 3 (a) Consider sending an IP datagram from Host E to Host F. Will Host E ask router RI to help forward the datagram? Why? In the Ethernet frame containing the IP datagram, what are the source and destination IP and MAC addresses? (b) Suppose E would like to send an IP datagram to B, and assume that E's ARP cache does not contain B's MAC address. Will E perform an ARP query to find B's MAC address? Why? In the Ethernet frame (containing the IP datagram destined to B) that is delivered to router Ri, what are the source and destination IP and MAC addresses? (c) Suppose Host A would like to send an IP datagram to Host B, and neither A's ARP cache contains B's MAC address nor does B's ARP cache contain A's MAC address. Further suppose that the switch S1's forwarding table contains entries for Host B and router R1 only Thus, A will broadcast an ARP request message. What actions will switch S1 perform once it receives the ARP request message? Will router R1 also receive the ARP request message? If so, will R1 forward the message to Subnet 3? Once Host B receives this ARP request message, it will send back to Host A an ARP response message. But will it sent an ARP query message to ask for A's MAC address? Why? What will switch S1 do once it receives an ARP response message from Host B? host S1 R1 S2 host host host subnet 1/2 subnet 3