3DN Standards Track — Informational
Category: Delta fabric / multi-agent hop language
Obsoletes: none
Updates: none

M2M: Model-to-Model Fabric Language
Version 0 (Draft)

Title

M2M — Model-to-Model Fabric Language

Version

0 (draft for implementation)

Status

Draft — published for interoperability; not an IETF RFC

Organization

3DN

Audience

Router implementers, agent authors, fabric operators

Bus context

Delta architecture: routers as the unit; human language and M2M as distinct hop payloads

Related

Delta, not river

1. Abstract

M2M is a compact fabric language for hops between software routers that host or front neural models. It is not a human natural language and not a claim of shared neural token IDs across vendors. M2M defines messages, a textual canonical form (for logs and debugging), and a binary on-wire form (for efficient hop payloads). Human languages (e.g. English) remain first-class on the fabric for desk and UI hops; seats declare preferred languages (e.g. English, M2M).

This document is published in the style of an RFC for clarity. It is a 3DN standards draft, not submitted to the IETF.

2. Conventions and terminology

The key words “MUST”, “MUST NOT”, “SHOULD”, and “MAY” are to be interpreted as described in RFC 2119 / RFC 8174 when used in uppercase.

3. Design goals

1. Heterogeneous models — Grok, Qwen, Claude, Codex, and local NNs share one hop envelope without shared tokenizer IDs.
2. Non-blocking fabric — submit a hop, continue work, wake on completion (no busy-wait requirement).
3. Dual representation — every field has a human-readable text form and a fixed binary encoding.
4. Start hard — normative BNF first; implementations MAY begin with the v0 compact stream subset.
5. Observable — text form MUST be loggable; binary form MUST round-trip to text form.

4. Non-goals

• Replacing HTTP, TCP, or TLS.
• A universal private neural code shared by all frontier vendors.
• Replacing English (or other human languages) on desk/UI hops.
• IETF standardization process (this page is intentional local SoT).

5. Core grammar (BNF)

ABNF-inspired BNF. Terminals in quotes; binary terminals described in §6.

; M2M v0 core grammar (normative intent)

m2m-document     = version-line 1*message

version-line     = "M2M" "/" version SP "CRLF"
version          = 1*DIGIT [ "." 1*DIGIT ]          ; e.g. 0 or 0.1

message          = msg-header CRLF msg-body
msg-header       = msg-type SP hop-id SP from-id SP to-id SP lang SP flags
msg-type         = "SUBMIT" / "PROGRESS" / "RESULT" / "ERROR"
                 / "CANCEL" / "WAKE" / "PING" / "PONG"
hop-id           = 16HEXDIG                         ; 64-bit id, hex
from-id          = router-token
to-id            = router-token
router-token     = 1*( ALPHA / DIGIT / "-" / "_" )
lang             = "EN" / "M2M" / 1*4ALPHA           ; short language code
flags            = 8BIT                             ; bit field, text as 8 binary digits or 0xHH

msg-body         = body-encoding SP body-length CRLF body-octets
body-encoding    = "TXT" / "BIN" / "JSON" / "C2C"
body-length      = 1*DIGIT                          ; decimal octet count
body-octets      = *OCTET                           ; exactly body-length octets

; Optional compact single-line result (v0 leaf implementations)
compact-result   = "M2M" "|" token-list "|" "score=" signed-float "|" "n=" 1*DIGIT
token-list       = token *( "," token )
token            = "t" 1*DIGIT ":" signed-float
signed-float     = [ "+" / "-" ] 1*DIGIT "." 1*DIGIT

CRLF             = %x0D.0A
SP               = %x20
HEXDIG           = DIGIT / "A" / "B" / "C" / "D" / "E" / "F"
                 / "a" / "b" / "c" / "d" / "e" / "f"

6. Lexicon: textual description and binary representation

Unless noted, multi-byte integers are network byte order (big-endian). Strings in headers are ASCII unless body-encoding says otherwise.

7. Message types

8. Wire framing

M2M messages ride on existing transport:

• TCP seat (mux agent port): optional CONTENT-LENGTH chat framing for human/English; for M2M api seats, body SHOULD be an M2M document or compact stream.
• HTTP leaf (e.g. local NN): POST /v1/forward with JSON {"prompt":…} returning {"language":"M2M","m2m":…} is a permitted v0 bridge.
• Control plane: jobs and image APIs remain HTTP; they MAY embed M2M bodies later.

Non-blocking intent: SUBMIT returns hop_id without requiring the caller to block; WAKE or RESULT is delivered to the submitter inbox when ready. Polling is allowed but not required.

9. Version 0 compact stream (implemented)

Early Delta NN leaves MAY emit a single-line compact RESULT without full headers:

compact-result = "M2M" "|" token-list "|" "score=" signed-float "|" "n=" length

This form is normative for v0 leaves and deprecated as a long-term sole format. Routers SHOULD accept it as shorthand for a RESULT message with lang=M2M and body-encoding=TXT.

10. Examples

10.1 Textual SUBMIT (English body)

M2M/0
SUBMIT 00a1b2c3d4e5f678 android01-mux delta-nn M2M 00001000
TXT 27
classify:disk pressure on edge LB

10.2 Compact M2M RESULT (v0 NN)

M2M|t0:-0.2082,t1:-0.1038,t2:-0.1741,t3:-0.0998,t4:-0.2408,t5:+0.2163,t6:+0.2386,t7:+0.2513|score=-0.0036|n=30

10.3 Binary frame sketch (hex, SUBMIT, empty body)

4D 32 4D 31          ; magic M2M1
01                   ; SUBMIT
00 A1 B2 C3 D4 E5 F6 78  ; hop_id
0B                   ; from len 11
61 6E 64 72 6F 69 64 30 31 2D 6D 75 78  ; "android01-mux" (len as configured)
08 64 65 6C 74 61 2D 6E 6E              ; to "delta-nn"
02                   ; lang M2M
08                   ; flags: wake-on-complete
01 00 00 00 00       ; TXT, length 0

11. Security considerations

• M2M does not provide authentication by itself. Deployments MUST place seats on trusted networks or terminate TLS/SSH externally.
• Body size limits and C2C references reduce amplification risk.
• ERROR bodies MUST NOT include secrets (tokens, passwords).
• Language code M2M MUST NOT be treated as executable code without a declared interpreter profile.

12. Registries (3DN local)

13. References

• 3DN, “Delta, not river: routers as the unit…”, 2026-09.
• RFC 2119 / RFC 8174 — requirement levels.
• RFC 5234 — ABNF (style reference for the BNF above).

End of 3DN M2M Version 0 (Draft). Revisions will bump the version line and preserve dual text/binary columns.