The Internet we know today is based on IPv4 (Internet Protocol). Because of the prospect of running out of addresses a new protocol for handling addresses was developed in 1996. It was called IPv6 (IPv5 Internet Streaming Protocol never materialised).
Scarcity of IPv4 adresses is now a reality, for instance in the APNIC region (Asia/Australia).
The allocation to DeiC of IPv6 addresses is the block 2001:0878::/32.