Each IPv6 address is represented by eight groups of four hexadecimal digits. A hexadecimal digit represents 4 bits, or 16 decimal units.

IPv6 is written in hexadecimal which uses the digits 0-9 and a-f. You can get try it out with our IPv6 subnetting practice. If you’ve been assigned a /48, how many /64s can you place inside it? These are the questions that IPv6 subnetting asks. Rather the concern is how many subnets fit within a certain network.

This can be a little hard to accept if you’re used to subnetting to conserve IPv4 addresses, but you need to change your mindset when working with IPv6 and realize that there is absolutely no need to worry about wasting addresses. This means that even if you have 200 devices on a single /64, you still have 2 64-200 of unused space. The subnet that is recommended for end host use in IPv6 is always a /64. With IPv6, conserving addresses is no longer a concern. Most experienced network engineers have become conditioned to using CIDR, VLSM, NAT and private addresses to conserve IPv4 space. Basically, a number too large for the human mind to grasp.Because of the enormity of the address space, IPv6 subnetting design follows different best practice. IPv6 allows almost 8*10 28 times as many addresses as IPv4. Each additional bit adds an additional ‘power of 2’ to the address space. So how large is the IPv6 address space? Intuitively it might seem like it’s 4 times bigger (128 compared to 32 bits), but it’s actually larger than that. The world has reached the point where there are not enough 32-bit addresses to link every device which wants to connect to the Internet.

The simple reason is that the IPv4 address space is running out.

Convert mac address to ipv6 calculator