/vscp-droplet

A VERY simple self forming network

Primary LanguageCMIT LicenseMIT

vscp-droplet

IMPORTANT - This project is now continued as vscp-espnow.

A VERY simple self forming network for wireless VSCP nodes

Warning!
There are secure and well though out mesh networks available. Use them!

Droplet model comes from dropping a water droplet and se the waves propagating through the water. Each event received by a node is retransmitted exactly one time if TTL > 1

Node types

Dumb node

  • Advertising. Raw Ethernet/Multicast/UDP/BLE
  • Configuration through USB/serial or similar.
  • Can be encrypted
  • All zones
  • All subzones

Standard node

  • Advertising. Raw Ethernet/Multicast/UDP/BLE
  • Receive broadcast.
  • Encrypted / Non-encrypted.
  • Direct BLE connectable.
  • Zone
  • Subzone
  • Configuration through USB/serial or similar.
  • Can use Friend node.

Friend node

  • Helper for 'mostly sleeping nodes'
  • Advertising. Raw Ethernet/Multicast/UDP/BLE
  • Receive broadcast. Collect events for friend(s).
  • Act as network extension.
  • Encrypted / Non-encrypted.
  • Direct BLE connectable.
  • Zone
  • Subzone
  • Configuration through USB/serial or similar.
  • Can use Friend node.

Bridge node

  • Bridge between topologies.
  • Advertising. Raw Ethernet/Multicast/UDP/BLE
  • Receive.
  • Encrypted / Non-encrypted.
  • Direct BLE connectable.
  • Configuration through USB/serial or similar, but also tcp/ip.
  • Can use Friend node.

Multicast

  • VSCP - 224.0.23.158
  • As with the other IP address classes, the entire 32 bits of the address is always used; we are just only interested in the least-significant 28 bits because the upper four bits never change.
  • Port is zone/subzone (0–65535).
  • 128-bit random key + encrypted payload.

UDP

  • Always broadcast
  • Port is zone/subzone (0–65535).
  • TTL
  • 128-bit random key + encrypted payload.

BLE

  • Advertising
  • zone/subzone in payload.

Provisioning

  • Send not-provisioned broadcast message every ten seconds.

Cryprographics modes

  • Open - no encryption
  • AES-128
  • AES-192
  • AES-256

Discovery

  • UDP Multicast every ten seconds to discover nodes in the surrounding area.
  • Unicast of event to found nodes in table.
  • Remove node from table if unavailable for n discoveries.

Resend

  • Event CRC used to detect if event has been seen.
  • Turn off resend from node x/y/z for a node. Used for nearby nodes.
  • Sender strange?

BLE

  • https://www.argenox.com/library/bluetooth-low-energy/ble-advertising-primer/
  • Advertising channels 37/38/39
  • 20ms to 10.24 seconds, in steps of 0.625ms. 0-10 ms random delay.
  • The Packet data unit for the advertising channel (called the Advertising Channel PDU) includes a 2-byte header and a variable payload from 6 to 37 bytes. The actual length of the payload is defined by the 6-bit Length field in the header of the Advertising Channel PDU.
  • ADV_IND and ADV_NONCONN_IND
  • ADV_IND is a generic advertisement and usually the most common. It’s generic in that it is not directed and it is connectable, meaning that a central device can connect to the peripheral that is advertising, and it is not directed towards a particular Central device.
  • ADV_NONCONN_IND is the advertisement type used when the peripheral does not want to accept connections, which is typical in Beacons.
  • Advertise: https://www.youtube.com/watch?v=BwGF_768B1U
  • Scan response: https://www.youtube.com/watch?v=6E4eW-lNKBE
  • Can I process OTA through Bluetooth® on ESP32? Yes, please operate basing on bt_spp_acceptor and bt_spp_initiator. If using Bluetooth LE, please operate basing on ble_spp_server and ble_spp_client.