“By moving many of the communication processing tasks (like NAT firewall traversal) to the Server, [Arrayent’s] gateway reference design has been implemented with a low BOM cost, about $4-$5, less than half the cost of ZigBee gateway implementations, and enables consumer product companies to add an RF radio to their product for less than $2.
https://www.pinestream.com/profile/152410/Arrayent?key=15r816P8km5Ao