Which of the following lists the three length/value fields in the IP header used to describe the datagram?

• A. IP Datagram Length, Fragmentation Offset, IP Protocol
• B. IP Header Length, IP Datagram Length
• C. IP Header Length, IP Datagram Length, Fragmentation Offset
• D. IP Header Length, Fragmentation Offset, TTL

Answer: (C)

Understanding which IPv4 header fields describe the size and fragmentation of a datagram. The IP Header Length (IHL) tells how long the header is, in 32-bit words, so you can determine the header size in bytes. The IP Datagram Length (Total Length) indicates the total size of the datagram, header plus data, in bytes. The Fragmentation Offset field shows where this fragment starts within the original datagram, using 8-byte units. Together, these three fields describe the datagram’s size and how it may be fragmented. Other fields like TTL or Protocol serve different purposes and do not describe size or fragmentation, so they aren’t part of the three length/value fields.