Rename FIPS Link Protocol (FLP) to FIPS Mesh Protocol (FMP)
The "Link Protocol" name understated the layer's scope — spanning tree
construction, bloom filter routing, greedy forwarding, and mesh-wide
coordination go well beyond link-level concerns. Rename fips-link-layer.md
to fips-mesh-layer.md, update FLP→FMP throughout docs and source code
(FLP_VERSION→FMP_VERSION, wire.rs, rx_loop.rs, spanning_tree.rs).
New SVG illustrations
- Protocol stack: color-coded layer diagram replacing ASCII art
- OSI mapping: side-by-side comparison with traditional networking layers
- Bloom filter propagation: 6-node tree with sender-colored filter boxes
showing split-horizon computation per link
- Routing decision flowchart: 5-step priority chain with candidate ranking
by tree distance and link performance
- Coordinate discovery: sequence diagram showing LookupRequest propagation,
response caching, and SessionSetup cache warming
Redesigned existing SVGs
- Architecture overview: uniform node layout, U-shaped encrypted link
connectors, separate end-to-end session line
- Node architecture: split Router Core into FSP and FMP layers, reorganize
transports into Overlay/Shared Medium/Point-to-Point categories
- Identity derivation: wider boxes, visible encode arrow, dashed npub line
fips-intro.md revisions
- Add inline references to prior work: Yggdrasil/Ironwood for coordinate
routing, Noise Protocol Framework for IK handshakes, WireGuard for
index-based session dispatch, Wikipedia for bloom filters, split-horizon,
and greedy embedding
- Add explanatory paragraphs after bloom filter diagram describing
split-horizon filter computation and candidate selection behavior
- Simplify transport abstraction language, remove I2P/LoRa references
- Fix LookupRequest wording ("propagates" not "floods"), note intermediate
node coordinate caching on lookup responses
- Rewrite architecture overview prose to match redesigned diagrams
- fips-architecture.md → fips-software-architecture.md with all
cross-references updated (4 files)
- fips-transport-abstraction.svg → fips-node-architecture.svg, moved
from Transport Abstraction section to Architecture Overview in
fips-intro.md
- Added descriptive paragraph for node architecture diagram covering
three-layer design (application interfaces, router core, transports)
Design change: Session layer now uses Noise IK pattern (previously KK),
matching the link layer. Rationale: initiator knows destination npub,
responder learns initiator identity from handshake - same asymmetry as
link connections.
Document consistency fixes:
- Auth* events → Noise IK msg1/msg2 terminology in state machines
- PeerId → NodeId in routing code examples
- BloomUpdate → FilterAnnounce terminology
- Updated cross-references and tables
Create fips-routing.md covering the complete routing architecture:
- Bloom filter design: 4KB filters, K=2 scope, event-driven updates
- Discovery protocol: LookupRequest/Response with signed proofs
- Greedy tree routing using coordinates from discovery
- Session establishment model for minimal data packet overhead
- Router coordinate caching with LRU eviction
Key design decisions:
- Leaf-only mode for constrained devices (single peer handles routing)
- Separation of discovery (find destination) from routing (deliver packets)
- Session setup pays coordinate cost once; data packets carry only addresses
- 36-byte data packet header comparable to IPv6
Update design docs README to include new document.
Move design documents from working directory into source tree:
- fips-design.md - Full protocol design specification
- spanning-tree-dynamics.md - Spanning tree protocol dynamics study
Add README index files for docs/ and docs/design/.
Johnathan Corgan