Cisco Certified Network Associate (CCNA) Practice Exam

In the IPv6 address structure, how many bits are included in each field?

1. 24

2. 4

3. 16

4. 128

The correct answer is: 16

In the IPv6 address structure, each field is composed of 16 bits. An IPv6 address is represented as eight groups of four hexadecimal digits, where each of these groups corresponds to a 16-bit chunk of the address. Therefore, when you break down the entire 128-bit address, it is divided into eight 16-bit fields. This structure allows for a significantly larger address space compared to IPv4. The other options do not accurately reflect the number of bits in each field of an IPv6 address. The value of 24 bits might refer to certain specific data formats or encapsulations but does not apply to the standard IPv6 structure. A value of 4 bits is too small for a field in this context, as it only represents a hexadecimal digit. Lastly, while 128 bits is the total length of the entire IPv6 address, it does not specify the size of an individual field.