IPV6 address , how many hosts can i go up for subnet 12

[Ibrahim Jamil]

Hello CISCO Fellow

with regard to below IPV6 address , how many hosts can i go up for subnet 12 , as u knew , in IPV4 up to 254 hosts per subnet , here how the situation looks like for this below ipv6 , How we calculate  how may host per subnet in ipv6

2001:DB8:6783:12::1/64

thanks all 

[johnd2310]

Hi,

Your subnet is a /64. Therefore, you have 64 bits for the network and 64 bits for the host portion. 64 bits for the hosts give you 2^64 hosts = 18446744073709551616 hosts

Thanks

John

[Ibrahim Jamil]

Hi Jhon

thanks for answering mate

do you you man the subnet 12 in the above ipv6 gives me 18446744073709551616 hosts ?

thanks mate

[Nagendra Kumar Nainar]

Ibrahim,

12 that you highighted in RED is part of your prefix. 2001:DB8:6783:12::/64 is your prefix and 64 is your mask.

The concept is similar to IPv4. Use the mask (64 in your case) to identify the bits for host by subtracting subnet-mask from 128 (host-bits=128-64 in your case) and use 2^(host-bits) to identify the number of hosts.

-Nagendra