Final answer:
The header length field would simply be the size of the header. If the header length is assumed to be 10 bytes, the correct answer is 'B. 10'. The total size of the packet would be 2869 bytes.
Step-by-step explanation:
If 2859 is the byte number of the payload's final byte, this does not directly determine the value of the header length field. The header length is a separate value that indicates the size of the header itself, not the payload. Assuming the header has a fixed size, such as 10 bytes, the total size of the packet would be the sum of the size of the payload and the size of the header. For instance, if the payload's final byte is at sequence number 2859 and the header is 10 bytes, the total size would be 2859 + 10, which is 2869 bytes. But the value of the header length field would simply be 10 bytes as assumed. So the correct answer would be 'B. 10' assuming the header length is 10 bytes.
The header length field indicates the length of the header in bytes. If the sequence number of the payload's final byte is 2859, we need to calculate the header length. Since the final byte's sequence number is 2859, it means that there are 2859 bytes in the payload. Assuming the header length is 10 bytes, we can calculate the total length of the message by adding the payload length and header length. Therefore, the total length value would be 2859 + 10 = 2869 bytes. However, the header length field only represents the length of the header, so the correct answer is option B. The value of the header length field would be 10.