2001:0DB8:AC10:FE01:0000:0000:0000:0020
Network Prefix
Subnet ID
Interface ID
Remember we are in hex so each character represents 4 bits (a nibble)
/16
/32
/48
/64
/96
/128
/80
/112
IPv6 is NOT Case Sensitive
https://www.networkworld.com/article/2223248/the-logic-of-bad-ipv6-address-management.html
The standard block being handed out for new networks is a /64