IPv6 EUI-64 explained

Hello CJ

Yes, you’re correct that theoretically, it is possible to generate a 36-bit (or any other size) Interface ID using random generation. However, the SLAAC process in IPv6 is designed to work specifically with /64 prefixes. This is because the /64 prefix divides the address into a network portion and a host portion, each of 64 bits.

The EUI-64 format is used to ensure globally unique addresses, but you could use randomly generated Interface IDs. But in both cases, the /64 division is maintained.

The main reason for this is standardization and simplicity. A /64 division simplifies subnetting and makes route aggregation more efficient. Changing this would require changes to the IPv6 protocol and could lead to compatibility issues. So, even if you’re not using EUI-64 and are using random generation, the /64 prefix is still used.

I hope this has been helpful!