Distinguish the address roles
01An IPv4-embedded IPv6 address carries 32 IPv4 bits. Its role depends on whether it represents an IPv4 node or is assigned to an IPv6 node for stateless translation.
Configured prefix plus IPv4 bits produces an address. Routing, packet translation and safe configuration are additional work, not outcomes guaranteed by this arithmetic.
Source for this drawing: RFC 6052 · Read RFC section 1.3 ↗
New to this? Start hereA quick picture + helpful background
A message needs an address.
Think of a packet as a small addressed envelope. Devices pass it onward; transport protocols decide what delivery promises an application gets.
Helpful first, if these ideas are unfamiliar
These pictures are analogies to help you learn. The linked RFC explains the actual rules.
Terms in this drawing
Related RFCs and changes
“Updates” changes part of an earlier RFC. “Obsoletes” replaces it. This list shows selected related documents.
An embedded address is a mapping, not a complete translation service.
- An embedded address is a mapping, not a complete translation service.
- IPv4-converted IPv6 addresses represent IPv4 nodes in an IPv6 network. IPv4-translatable IPv6 addresses are assigned to IPv6 nodes for stateless translation. Both use the same §2.2 format.
- The Well-Known Prefix is 64:ff9b::/96. A Network-Specific Prefix is chosen for an organization. Packet translation, DNS synthesis and prefix discovery need other mechanisms.
The scenes show address identities, not packet encapsulation or a DNS query. Stateful means per-flow state exists; stateless means no per-flow state is required. All 2001:db8 and 192.0.2 examples are documentation values. Even the published Well-Known Prefix example is a format example, not permission to translate documentation traffic under §3.1.
Read the RFC section ↗