What protocol enables mesh communications on Xenon/Argon?

[ScruffR]

Here is one post that might help

Particle Announces Three New IoT Products and Particle Mesh Shipping At Spectra

@barry65, Xbee uses a the Zigbee protocol on top of the 802.15.4 protocol. The Particle mesh uses OpenThread on top of 802.15.4 which is not compatible with Zigbee.