Neighbor propagation (ORP-006)
Neighbor propagation (decision ORP-006, SPEC §13) defines how presence and routing state moves between neighboring board nodes, so that a rendezvous can complete even when the two parties reach different nodes.
The problem propagation solves
Section titled “The problem propagation solves”A single board node only knows about the parties connected to it. If two parties that share a key land on different nodes, the rendezvous cannot complete unless the nodes share enough state to route between them. Neighbor propagation is that sharing.
How state propagates between neighbors
Section titled “How state propagates between neighbors”Neighboring nodes propagate the routing state they need (opaque tags, not
contents) so a frame can find its counterpart on another node. The
core/propagation module implements this. TODO: confirm the propagation mechanism, what is shared, and the topology assumptions against SPEC §13.
Preserving blindness across nodes
Section titled “Preserving blindness across nodes”Propagation must not widen what any node can read. Only the opaque tags
needed for routing cross between neighbors; sealed payloads stay sealed and
contents stay unreadable, so adding nodes does not weaken the blindness
invariant. TODO: confirm that the propagated state is limited to opaque routing tags.
Source: SPEC §13 (neighbor propagation, ORP-006); core/propagation. TODO: confirm the mechanism and what state is shared (see OPEN-QUESTIONS.md).