Node Identity

The node identity payload is an application-layer structure carried inside the UMSH payload. Its contents — including the timestamp below — are not interpreted or required by the MAC layer. The MAC layer itself is timestamp-free (see Frame Counter).

A node’s identity may be expressed as the following structure:

• 4 bytes: UNIX timestamp from when this information was last updated, truncated to 32 bits
• 1 byte: Node primary role
• 1 byte: Node feature/capability bitmap
• N bytes, optional: zero-terminated node name
• N bytes, optional: CoAP-style option list, terminated by 0xFF if EdDSA signature is present.
• 64 bytes, optional: EdDSA signature over the preceding identity data

Node Primary Role

Defined values:

• 0 — Unspecified
• 1 — Repeater
• 2 — Chat
• 3 — Tracker
• 4 — Sensor
• 5 — Bridge
• 6 — Chat Room
• 7 — Temporary Session
• all other values — Reserved

Capability Bitmap

Bit assignments:

• bit 0 — Repeater
• bit 1 — Mobile
• bit 2 — Text Messages
• bit 3 — Telemetry
• bit 4 — Chat Room
• bit 5 — CoAP
• bit 6 — Node name included
• bit 7 — Node options included

If the node-name-included bit is clear, the node name is simply not advertised in this identity payload; it does not imply the node lacks a name.

Node Identity Options

Possible options include:

• Node Location (longitude/latitude)
• Node Battery Percentage
• Node Uptime (minutes)
• Amateur Radio Callsign
• Supported Regions (for repeaters)

Signature Usage

The optional 64-byte EdDSA signature is generally included only when the identity data must stand on its own, such as:

• QR codes
• broadcasts without a MIC

When the enclosing packet already carries a MIC, the EdDSA signature is generally omitted.