Files
fips/docs/design
Johnathan Corgan f825fa242f Hybrid coordinate warmup: CoordsWarmup message and proactive fallback
Implement hybrid coordinate cache warming strategy: piggyback coords
via CP flag when they fit within transport MTU, send standalone
CoordsWarmup (0x14) message when they don't. On CoordsRequired or
PathBroken receipt, send CoordsWarmup immediately with source-side
rate limiting (default 2s per destination, configurable).

- Add CoordsWarmup = 0x14 session message type (empty body, CP flag)
- Add send_coords_warmup() following send_session_msg() pattern
- Restructure send_session_data() to send standalone warmup before
  data packet when piggybacked coords exceed MTU
- Add immediate CoordsWarmup response in handle_coords_required()
  and handle_path_broken() with per-destination rate limiting
- Add coords_response_interval_ms config (node.session)
- Add RoutingErrorRateLimiter::with_interval() constructor
- Zero transit-path changes: existing try_warm_coord_cache() handles
  CoordsWarmup identically to CP-flagged data packets
- Update design docs (session layer, wire formats, mesh operation,
  configuration)
2026-02-19 15:25:30 +00:00
..

FIPS Design Documents

Protocol design specifications for the Federated Interoperable Peering System — a self-organizing encrypted mesh network built on Nostr identities.

Reading Order

Start with the introduction, then follow the protocol stack from bottom to top. After the stack, the mesh operation document explains how all the pieces work together. Supporting references provide deeper dives into specific topics.

Protocol Stack

Document Description
fips-intro.md Protocol introduction: goals, architecture, layer model
fips-transport-layer.md Transport layer: datagram delivery over arbitrary media
fips-link-layer.md FIPS Link Protocol (FLP): peer authentication, link encryption, forwarding
fips-session-layer.md FIPS Session Protocol (FSP): end-to-end encryption, sessions
fips-ipv6-adapter.md IPv6 adaptation: TUN interface, DNS, MTU enforcement

Mesh Behavior

Document Description
fips-mesh-operation.md How the mesh operates: routing, discovery, error recovery
fips-wire-formats.md Wire format reference for all message types

Supporting References

Document Description
fips-spanning-tree.md Spanning tree algorithms: root election, parent selection, coordinates
fips-bloom-filters.md Bloom filter math: FPR analysis, size classes, split-horizon

Implementation

Document Description
fips-software-architecture.md Stable architectural decisions guiding the codebase
fips-state-machines.md Phase-based state machine pattern (Rust enum-of-structs)
fips-configuration.md YAML configuration reference

Supplemental

Document Description
spanning-tree-dynamics.md Spanning tree walkthroughs: convergence scenarios, worked examples

Document Relationships

                        fips-intro.md
                             │
              ┌──────────────┼──────────────┐
              ▼              ▼              ▼
   fips-transport-layer  fips-mesh-     fips-software-
              │          operation       architecture
              ▼              │              │
   fips-link-layer ◄────────┤              ▼
              │              │       fips-state-machines
              ▼              │
   fips-session-layer        ├──► fips-spanning-tree
              │              │         │
              ▼              └──► fips-bloom-filters
   fips-ipv6-adapter
                        fips-wire-formats
                        (referenced by all layer docs)

              fips-configuration
              (standalone reference)

              spanning-tree-dynamics
              (pedagogical companion to fips-spanning-tree)