Low Powered Mesh Network stack

Features

Addressed network with auto-retries, and auto-acknowledge
Minimal RAM/ROM footprint, with NO HEAP usage
Each node can participate in the mesh network to deliver packets to a destined node.
Each packet may dictate maximum hops it can take.
Self-Healing Routes.
Routes are rediscovered and deleted as appropriate.

Acknowledgment

Inspiration was taken from Atmel's lightweight mesh, however, the code was completely rebuilt from the ground up and detailed testing was performed during each development step. In general, simplicity was favored and a clean API was targeted such that integration with projects for the open-source community can benefit.

Detailed Features

Each packet sent can use existing route, and if route has changed, a new route is automatically discovered using a special retry packet.
Each node's ACK contains some piggy-back data about the node itself.
This data includes information about its routing table, and other statistics
Duplicate packets are absorbed but an ACK is still replied if its a duplicate, but a retry packet.
An ACK packet or a response to an ACK all use retries; even the repeating nodes participate to make sure the packet is delivered.

There is no "out-of-the-box" support for sleeping nodes, however, any sleeping node can wake up, transmit a packet and go back to sleep without affecting the rest of the network. This mesh network design doesn't rely on any node to be a medium as routes can change dynamically. With this said, there are a few improvements that could be made :

Use RSSI to dictate if a route should be changed.
Use a counter to prefer a route that sends us data more often.

Payload

The minimum payload is 9 bytes, of which, 8 bytes will be the mesh header overhead. The higher the payload, the higher the efficiency of the network. The eight bytes of payload header contains the network source and destination information, along with packet type and hop count information.