Question

Consider the following range of addresses;

2001:0DB8:BC15:0000:0000::
2001:00B8:BC15:00A1:0000::
2001:00B8:BC15:00A2:0000::
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2001:00BB:BC15:00AF:0000::

Give the right prefix-length for the range of addresses given. Show your calculation work that derives to your answer.

Answer 1

The correct prefix-length for the given range of IPv6 addresses is /22, found by comparing the common bits in the starting and ending addresses up to the point of difference.

Step-by-step explanation:

To determine the prefix-length for the given range of IPv6 addresses, you must compare the starting and ending addresses and find the longest common sequence of bits from the left. Let's analyze the first and last addresses:

• 2001:00B8:BC15:0000:0000::
• 2001:00BB:BC15:00AF:0000::

The common bits up to the seventh hexadecimal segment are 2001:00B. The difference starts at the fourth hexadecimal digit of the third segment, where we have 8 and B (1000 and 1011 in binary). Thus, the first 22 bits are common (3 segments * 4 hexadecimal digits per segment = 12 hexadecimal or 48 bits; minus the 2 bits difference in the fourth digit = 22 bits). So, the prefix length is /22.