Figure 1 is an interactive activity that allows the learner to practice matching a description of an IP header field with its name.  The fields in this activity are version, time to live, source IP address, destination IP address, differentiated services and protocol. Figure 2 is an interactive activity that allows the learner to practice matching a description of more IP header fields with their name.  The fields in this activity are Internet header length, total length and header checksum.