MAP-E: draft-03 and RFC 7597
This documentation is still being edited and may differ from the actual version.
This is extra reading. You do not need to understand the history of MAP-E’s two specifications (draft and RFC) before configuring Flet’H.
Short version: draft is usually not a separate line service. It is usually a legacy implementation, compatibility mode, or old name. What matters for connectivity is whether the calculated MAP-E parameters match the ISP / VNE rules.
What MAP-E RFC means
Section titled “What MAP-E RFC means”The final MAP-E specification is RFC 7597. It defines MAP rules for carrying IPv4 over IPv6, including:
- IPv4 prefix
- IPv6 prefix
- EA bits
- PSID length
- offset
- BR address
- usable port set
In MAP-E mode, Flet’H ultimately cares about the same results: IPv4 address, BR address, PSID, offset, and usable port ranges.
What draft means
Section titled “What draft means”On Japanese IPv4 over IPv6 lines and older OpenWrt scripts, you may see labels such as MAP-E(draft), draft, or older map implementations.
This specifically refers to draft-ietf-softwire-map-03, an early draft of MAP-E before it became a formal RFC. Since Japanese VNEs (such as JPNE) deployed their services early, before RFC 7597 was finalized, many early implementations and documents are based on the -03 draft.
These usually mean:
- Implementation or naming left over from early draft-03 era MAP-E.
- Compatibility behavior in older OpenWrt
mapscripts for this draft. - Old field names used by some line or device documents.
- UI or config labels that still say
draft.
It does not mean “not MAP-E”, and it does not mean the line is necessarily broken.
Technical differences between draft and RFC
Section titled “Technical differences between draft and RFC”Although both are called MAP-E, draft-03 and the final RFC 7597 are not identical. The differences directly relevant to Flet’H are:
| Area | draft-03 (early draft) | RFC 7597 (final standard) |
|---|---|---|
| MAP CE IPv6 address layout | Embeds the IPv4 address and PSID at the positions defined by draft-03 | Uses the different interface-identifier layout defined by RFC 7597 Section 6 |
| Default PSID offset | 4 | 6; a rule may specify another value, so offset 4 alone does not prove that draft mode is in use |
| Port-set algorithm | Uses the infix / GMA A | PSID | M layout | Retains the same basic layout; the port formula alone does not distinguish draft from RFC |
Commercial MAP-E services in Japan use draft-ietf-softwire-map-03. Flet’H likewise calculates the parameters and constructs its MAP-E tunnel in draft-03 compatibility mode; it does not use the RFC 7597 implementation format.
For troubleshooting, compare the actual IPv4 address, BR, PSID, offset, port set, and local MAP-E IPv6 address with the ISP / VNE values. Do not decide from the draft or RFC label alone.