Files
fips/docs/design
Johnathan Corgan dc12b4a82e Migrate session-layer addresses from FipsAddress to NodeAddr
Session packet headers use 32-byte NodeAddr (SHA-256 of pubkey) for
routing, not 16-byte FipsAddress (IPv6 ULA). Update all session-layer
structs (SessionDatagram, SessionSetup, SessionAck, DataPacket,
CoordsRequired, PathBroken) and CoordCache to use NodeAddr.

- DATA_HEADER_SIZE: 36 → 68 (two 32-byte addresses + 4 bytes overhead)
- CoordCache: HashMap key FipsAddress → NodeAddr
- Docs: fix header sizes in session-protocol and routing docs
- All 265 tests updated and passing
2026-02-06 13:48:36 +00:00
..

FIPS Design Documents

Protocol design specifications and analysis for the Federated Interoperable Peering System.

Suggested Reading Order

Start with the high-level architecture, then work through session flow, routing concepts, and finally the wire-level protocol details.

1. Introduction and Overview

Document Description
fips-intro.md Protocol introduction: goals, concepts, architecture

2. Protocol Flow (How Traffic Works)

Document Description
fips-session-protocol.md End-to-end session flow, Noise IK encryption, terminology

3. Routing (How Packets Find Their Way)

Document Description
fips-routing.md Routing concepts: bloom filters, discovery, greedy routing
spanning-tree-dynamics.md Tree protocol behavior: convergence, partitions, recovery
fips-gossip-protocol.md Wire formats: TreeAnnounce, FilterAnnounce, Lookup messages
Document Description
fips-wire-protocol.md Transport layer: Noise IK, session indices, roaming, security
fips-transports.md Transport-specific: UDP, Ethernet, Tor, radio characteristics

Implementation

Document Description
fips-architecture.md Software architecture: entities, state machines, configuration
fips-tun-driver.md TUN interface driver: reader/writer threads, ICMPv6, packet flow
fips-state-machines.md Phase-based state machine pattern: peer lifecycle, transitions

Document Cross-References

                      fips-intro.md
                           │
              ┌────────────┴────────────┐
              ▼                         ▼
    fips-session-protocol.md    fips-architecture.md
              │                         │
    ┌─────────┴─────────┐               ▼
    ▼                   ▼         fips-transports.md
fips-routing.md   fips-wire-protocol.md
    │       │
    ▼       ▼
spanning-tree-dynamics.md ←→ fips-gossip-protocol.md