CISCO CCNA 200-301 Q191

Which is the shortest possible notation of the following Internet Protocol version 6 (IPv6) address?

2001:0DB8:0000:0001:0000:0000:0000:F00D

A. 2001:DB8::1::F00D
B. 2001:DB8:0:1::F00D
C. 2001:DB8:0:1:0:0:0:F00D
D. 2001:0DB8:0:1::F00D

Correct Answer: B

Explanation:
The shortest possible notation of the IPv6 address 2001:0DB8:0000:0001:0000:0000:0000:F00D is 2001:DB8:0:1::F00D. The address is shortened according to the following rules:

– Remove leading zeros.
– Remove the consecutive fields of zeros with double colon (::).
– The double colon (::) can be used only once.

The option 2001:DB8::1::F00D is incorrect because the double colon (::) can be used only once in the process of shortening an IPv6 address.

The option 2001:DB8:0:1:0:0:0:F00D is incorrect because 2001:DB8:0:1:0:0:0:F00D can be further shortened to 2001:DB8:0:1::F00D.

The option 2001:0DB8:0:1::F00D is incorrect because 2001:0DB8:0:1::F00D can be further shortened to 2001:DB8:0:1::F00D.