Expanding the IPv6 Documentation Space

The document describes the reservation of an additional IPv6 address prefix for use in documentation. This update to RFC 3849 expands on the existing 2001:db8::/32 address block with the reservation of an additional, larger prefix. The addition of a /20 prefix allows documented examples to more closely reflect a broader range of realistic, current deployment scenarios and more closely aligns with contemporary allocation models for large networks.