1. What is the difference between packet fragmentation (i.e., at network layer) and frame fragmentation (i.e., at link layer) in terms of purpose? 2. Suppose that host A is connected to a router R1, R1 is connected to another router, R2, and R2 is connected to host B. Suppose that a TCP message that contains 800 bytes of data and 20 bytes of TCP header is passed to the IP function at host A for delivery to B. Show the Total length, DF, MF, and Fragment offset fields of the IP header in each packet transmitted over the three links. (Assume that link A-R1 can support a maximum frame size of 1024 bytes including a 14-byte frame header, link R1-R2 can support a maximum frame size of 512 bytes, including an 8-byte frame header, and link R2-B can support a maximum frame size of 432 bytes including a 12-byte frame header.) (*hint: the Fragment offset field is denominated by 8-bytes, not bytes) 3. What is the purpose of the path MTU discovery process (see textbook Figure 5-42) and why does it need to set the DF bit in the IP headers