So I can either have this device be a separate device, or I can build this capability into all devices, which would raise the cost of each considerably. I am trying to figure out the correct balance between maximum flexibility and ease of use for everyone, and hardware cost and simplicity.

On a most basic level, the gateway is different than the other devices. So it would make all the other devices vastly more complicated if they had to also perform gateway functions. And it would make the system itself much more complex, as each element of the system would need to dynamically figure out what its role is. For ex, with Zigbee, a device is a coordinator or a router or an end device. In my basic concept, all devices are routers. But if I build gateway functionality into all devices, then…

Scenarios

1. Single Ethernet device: when a device is the only device, it is connected to the network (local or global) through a router, and uses Ethernet only. Radio is unused? No, device probably thinks it is a Zigbee gateway and Zigbee coordinator, and passes data into the local radio space.
2. Two (or more) devices, one connected to Ethernet and one (or more) out in the aiosphere: I believe this is simple and straightforward, and the device which is connected via Ethernet assumes correctly that it is the sole bridge, gateway and coordinator. And the devices which receives connection via radio knows it is a router/end device.
3. Two devices, both connected via Ethernet: this is tricky, in that it asks the devices, or the controlling system, or the user, to tell them what is going on. As they would both default to Zigbee coordinator roles, there would be problems. Unless the Zigbee system I choose has some automatic negotiation for such a system. Somehow one of the devices must be both a gateway and a coordinator, and the other must be an end device (then does it get its data through Ethernet, or radio? Who decides, and how?)

Solution A

1. Make a fixed gateway device,
2. Require that only one of these devices be present in a system,
3. Make all other devices radio only.

Solution B

1. Make all devices have both Ethernet and radio links
2. Make all devices capable of gateway, coordinator and router/end device functions.
3. Come up with some arbitration scheme where all scenarios can easily be resolved into a single functioning network with one gateway, one coordinator, and the rest of the devices router/end devices.

Advantages of solution B

• User simply buys devices and plugs them in, not worrying about anything, and they just work.
• All devices are functional, there are no ugly black boxes that don’t provide aiosphere end device functionality.
• There are no network setup steps, no multiple types of devices, no rules abut what goes where for the user to follow.

Disadvantages of solution B

• All devices have gateway, coordinator and router functionality.
• All devices have both radio and Ethernet hardware.
• All devices have Ethernet and power jacks.
• All devices are much more complex and much more expensive.
• Small end-device devices, such as battery operated devices, don’t follow this model. So even with this model, the user still eventually needs to deal with the concept of different types of devices?