# Mesh Model

FreeDMR is a peer network, not hub-and-spoke. Local sysops retain policy autonomy.

The guiding principle remains "everything everywhere", subject to source quench, STUN, ACLs, local policy, authentication, loop-control, and documented exceptions.

## Loop Control and Bridge Control

Loop control, source selection, duplicate suppression, source quench, and STUN are packet-plane safety mechanisms.

Source quench is a control hint to suppress a stream/TG toward a peer. It is optional and scoped per stream/TG.

STUN is a broader FBP/OpenBridge traffic gate. Under the current conceptual model, `BCST`/STUN applies to all FBP traffic from that peer until cleared or expired by policy.

`BCSQ` is per stream/TG.

`BCST`/STUN is all FBP traffic.

## Protocol Versions and Metadata

Source server and source repeater metadata must be preserved according to the protocol version actually in use for that session.

OBP/FBP protocol version controls metadata layout and option order.

Protocol v1 OBP remains an important open interop path where intentionally configured. FBP v5 is the current richer peer-server protocol target. FBP v4 is historical/deprecation context unless explicitly retained.

## TG Namespace Rule

HBP/RF-visible TG and FBP/OBP-visible conference TG can intentionally differ, especially with dial-a-TG.

Source quench must use the TG namespace visible to the peer sending or receiving the quench.

For HBP-to-FBP dial-a-TG, `BCSQ` should use the FBP/reflector TG, not local RF TG9.

For OBP-source traffic, `BCSQ` should use the inbound OBP TG because that is the source-server namespace.

## Open Questions

- Final FBP v5 identity/auth fields still need a concrete wire-format decision.
- STUN recovery policy needs an operator workflow, likely API-driven.