1. (10 pts) ARP and Switch Self-Learning

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   The following network has 9 hosts (A-F) and 4 switches (S1-S4) marked with link numbers. Suppose that host A and D have completed DHCP and so they both know their own IP address. Also, the IP address of D is already known to A.

1. Now, an application in Host A gives a small message to a UDP socket to deliver the message to host D. Explain which packets are sent by host A and which packets are sent by host D.
2. 1. Now suppose that the application in host D generates a UDP response. Explain which packets are sent by Host D and which packets are sent by Host A.
4. 2. Assuming all switch forwarding tables are initially empty, fill each switch's forwarding table after both operations described above are performed.

5. S1

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   Dest.	Port

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