You are configuring the IPv6 network infrastructure for a branch office.
The corporate network administrator allocates the 2001:DB8:0:C000::/58 address space for use in
the branch office.
You need to identify the maximum number of IPv6 subnets you can create.
How many IPv6 subnets should you identify?
A.
32
B.
64
C.
128
D.
1024
Explanation:
IPv6 has 128-bit (16-byte) source and destination IP addresses. Although 128 bits can express over
3.4×1038 possible combinations, the large address space of IPv6 has been designed for multiple
levels of subnetting and address allocation from the Internet backbone to the individual subnets
within an organization.
http://technet.microsoft.com/en-us/library/dd379516%28v=WS.10%29.aspx
Found this helpful method on another site by someone.
The default v6 address is a /64 just like the v4 is a /24 2) use the default mask so: 64 – 58 = 6 then 2 to the power of 6 = 64 ;o) easy way to figure it out. another example for a /57 – 64 – 57 = 7 …. 2 to the power or 7 is 128