Meshtastic adds relay tracking to reveal packet paths

Meshtastic’s pull request #10767, opened by alecperkins and titled Provide relay info for outbound packets and about subsequent relays, pushed the firmware toward showing the path a packet actually took through the mesh.

Meshtastic’s mesh algorithm documentation includes packet headers with a 1-byte Next-hop field and a 1-byte Relay Node field, so the new tracking work extends an existing header design instead of inventing relay tracking from scratch. Meshtastic’s managed flooding model has every radio that receives a packet rebroadcast it up to a hop limit, but first wait briefly and listen to avoid redundant repeats. In an August 18, 2024 blog post, Meshtastic tested smarter routing approaches but had not found one that consistently beat managed flooding for its use cases.

Relay visibility can show whether a rooftop node is really carrying neighborhood traffic, whether a valley crossing is being bridged by the node everyone assumed was handling it, and whether a mesh has an unexpected weak spot where packets are dying or being repeated too often. It also gives client builders better raw material for dashboards, packet logs, and network maps, and it gives maintainers a way to compare mesh behavior with role assignments.

Meshtastic’s February 26, 2025 2.6 preview said next-hop routing for direct messages had been 1.5 years in the making, and noted that the project reused two unused bytes in the unencrypted header to store the current relayer and the next-hop it expected to use. The project’s traceroute module already shows the path a message took to reach its destination.

Meshtastic describes itself as an open-source, decentralized mesh networking ecosystem built around LoRa radios for off-grid communication, and a community readme puts group size in the rough range of 30 to 200 nodes depending on settings.