What is the maximum number of 32-bit words specified by the IHL field in the IPv4 header?

What is the maximum number of 32-bit words specified by the IHL field in the IPv4 header?

• A. 8
• B. 10
• C. 12
• D. 15

Answer: (D)

The IHL (Internet Header Length) field in the IPv4 header specifies the length of the IPv4 header in 32-bit words. The IHL field is a 4-bit field, meaning it can represent values from 0 to 15, which corresponds to the number of 32-bit words. Therefore, the maximum value that can be represented is 15, which equals a maximum header size of 15 x 4 = 60 bytes. This allows flexibility in the size of the header due to optional fields, enabling the inclusion of additional information as needed, which is crucial for supporting various functionalities in the IPv4 protocol. This context clarifies that the answer identifies the upper limit of how many 32-bit increments can be included in the standard header definition.

The IHL (Internet Header Length) field in the IPv4 header specifies the length of the IPv4 header in 32-bit words. The IHL field is a 4-bit field, meaning it can represent values from 0 to 15, which corresponds to the number of 32-bit words. Therefore, the maximum value that can be represented is 15, which equals a maximum header size of 15 x 4 = 60 bytes. This allows flexibility in the size of the header due to optional fields, enabling the inclusion of additional information as needed, which is crucial for supporting various functionalities in the IPv4 protocol. This context clarifies that the answer identifies the upper limit of how many 32-bit increments can be included in the standard header definition.