Stuart Longland (VK4MSL)A silly protocol idea has been brewing in my mind… CoAP over AX.25.
The thinking is this… use UI frames to encapsulate CoAP messages in the same manner as UDP and use a URI scheme like coap+ax25://DEST[,DIGI1[,DIGI2…]]/[path]
If DEST has the C/H bit clear, DEST is a "multicast" group, otherwise it's a specific amateur station.
File transfer just uses RFC-7959 [block-wise transfer] (with possibly a small extension inspired by RFC-2090 [TFTP Multicast] to allow Block1 transmissions to a multicast group).
That would allow file transfer and messaging between stations using existing AX.25 packet radio hardware.
- https://datatracker.ietf.org/doc/html/rfc7252 - CoAP RFC
- https://datatracker.ietf.org/doc/html/rfc7959 - Blockwise transfers over CoAP
- https://datatracker.ietf.org/doc/html/rfc2090 - TFTP Multicast
- https://ax25.net/ - AX.25 protocol specs and docs
RFC 7252: The Constrained Application Protocol (CoAP)
The Constrained Application Protocol (CoAP) is a specialized web transfer protocol for use with constrained nodes and constrained (e.g., low-power, lossy) networks. The nodes often have 8-bit microcontrollers with small amounts of ROM and RAM, while constrained networks such as IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs) often have high packet error rates and a typical throughput of 10s of kbit/s. The protocol is designed for machine- to-machine (M2M) applications such as smart energy and building automation. CoAP provides a request/response interaction model between application endpoints, supports built-in discovery of services and resources, and includes key concepts of the Web such as URIs and Internet media types. CoAP is designed to easily interface with HTTP for integration with the Web while meeting specialized requirements such as multicast support, very low overhead, and simplicity for constrained environments.
oneM2M-The Global IoT Standard
Luca Barbato
chrysn
Julien Vermillard
Habr