1. Select the first ICMP Echo Request message sent by your computer, and expand the Internet Protocol part of the packet in the packet details window. What is the IP address of your computer? 2. Within the IP packet header, what is the value in the upper layer protocol field? 3. How many bytes are in the IP header? How many bytes are in the payload of the IP datagram? Explain how you determined the number of payload bytes. 4. Has this IP datagram been fragmented? Explain how you determined whether or not the datagram has been fragmented. Next, sort the traced packets according to IP source address by clicking on the Source column header; a small downward pointing arrow should appear next to the word Source. If the arrow points up, click on the Source column header again. Select the first ICMP Echo Request message sent by your computer, and expand the Internet Protocol portion in the "details of selected packet header" window. In the "listing of captured packets" window, you should see all of the subsequent ICMP messages (perhaps with additional interspersed packets sent by other protocols running on your computer) below this first ICMP. Use the down arrow to move through the ICMP messages sent by your computer. 5. Which fields in the IP datagram always change from one datagram to the next within this series of ICMP messages sent by your computer? 6. Which fields stay constant? Which of the fields must stay constant? Which fields must change? Why