Quiz 7 1. Which field in an IP datagram always changes from one datagram to the next in a series of ICMP messages sent from your computer. i. What always changes is the identification, checksum, time to live, and fragment existence. 2. Which fields are constant values? Which fields should remain constant? Which fields should change? Why? i. Constant values IP version, header length, Protocol, source and destination, total length ii. Must be Constant: IP version, header length, TTL iii. Must change : fragment number, sequence number, flags, total length and checksum iv. That should be constant because it's a fixed value. While the one that must change because the value must be unique 3. Describe the pattern you see in the values in the IP datagram identification field Next, still with the packets sorted by source address, look for a series of ICMP TTLexceeded replies sent to your computer from a nearby router. i. The pattern always seems to change, which is the increment or addition of a constant value of 1. 4. What is the content of the Identification field and TTL field? Are the values of all ICMP TTL-exceeded responses sent to your computer from the nearest router (first hop) unchanged? Why? i. In field identification, the value always changes and decreases, while the TTL is fixed.