Mesh network

Powerful way to route observations. Range is extended by allowing data to hop node to node and reliability is increased by “self healing”, the ability to create alternate paths when one node fails or a connection is lost. It has the following advantages:

• Network setup is simpler
• More flexibility to expand the network
• Increased reliability in environments where routers may come and go due to interference or damage

Digi XBee radio configuration

Below you will find the required configuration for the XBee radios used in the M2MBridge Mesh Network. Using Digi XCTU tool you need to do the following:

• Set the baud rate to 230400 [8]
• Set the API enable setting to API mode without Escapes [1]

serial configuration

• Make sure that all bridges participating in the same mesh network share the same network identifier. Multiple mesh network can operate in the same zone as long they have different Network IDs.

network identifier

Assumptions

1. the XBee 900HP radio has been configure with digimesh firmware https://www.digi.com/support/productdetail?pid=5576&type=firmware
2. the XBee 900HP radio must be connected to /dev/ttyUSB0 with this configuration: 230400/8/N/1/N - API 1

M2MBridge Configuration

Once the initial configuration of the XBee device is done and the XBee is attached to the device that is running the M2MBridge service, a mesh network configuration needs to be set up. You can find more information about these configuration settings in this page

Mesh Network autodiscovering

The autodiscovering of nodes in the M2MBridge network of XBee devices starts in the bootstrap process of the M2MBridge service. In an M2MBridge mesh network of XBee devices there are two different types of actors:

• Master
• Node

The master is in charge of organizing the discovering and distributing information about the known nodes in the network. They start listening for messages from other nodes in the network and enrich the collection of known nodes. Then they broadcast this information in the network so that all the nodes in the network know about all the available peers. This way, a P2P communication is established and every node in the network is capable of communicating with each other.

A node, on the other hand, starts broadcasting their information in the bootstrap until there is a master ready for listening and replies back with a collection of known nodes where its information is contained. This way, it guarantees that the master knows of its existence.

There is no strict order for starting up nodes in a M2MBridge mesh network. No matter what role a node play in the network, it will always make its best effort guaranteeing that every other node in the network knows of its existence.