Amazon's ad-hoc Ring, Echo mesh network can mooch off your neighbors' Wi-Fi if needed – and it's opt-out

Amazon is close to launching Sidewalk – its ad-hoc wireless network for smart-home devices that taps into people's Wi-Fi – and it is pretty much an opt-out affair.

The gist of Sidewalk is this: nearby Amazon gadgets, regardless of who owns them, can automatically organize themselves into their own private wireless network mesh, communicating primarily using Bluetooth Low Energy over short distances, and 900MHz LoRa over longer ranges.

At least one device in a mesh will likely be connected to the internet via someone's Wi-Fi, and so, every gadget in the mesh can reach the 'net via that bridging device. This means all the gadgets within a mesh can be remotely controlled via an app or digital assistant, either through their owners' internet-connected Wi-Fi or by going through a suitable bridge in the mesh. If your internet goes down, your Amazon home security gizmo should still be reachable, and send out alerts, via the mesh.

It also means if your neighbor loses broadband connectivity, their devices in the Sidewalk mesh can still work over the 'net by routing through your Sidewalk bridging device and using your home ISP connection.

The range is also said to be greater than that of Wi-Fi, meaning you can place Sidewalk-capable smart-home devices where Wi-Fi can't reach them yet where they can join a nearby Sidewalk mesh. And it's hoped the mesh can be used to locate missing items or pets: fit them with a Sidewalk-capable widget, such as a Tile, and they can be found within the range of a mesh.

Amazon Echoes, Ring Floodlight Cams, and Ring Spotlight Cams will be the first Sidewalk bridging devices as well as Sidewalk endpoints. The internet giant hopes to encourage third-party manufacturers to produce equipment that is also Sidewalk compatible, extending meshes everywhere.

Crucially, it appears Sidewalk is opt-out for those who already have the hardware, and will be opt-in for those buying new gear. From Amazon's privacy whitepaper [PDF] on this new, proprietary technology:

In other words, if you already have, say, an Amazon Ring, it will soon get a software update that will automatically enable Sidewalk connectivity, and you'll get an email explaining how to switch that off. When powering up a new gizmo, you'll at least get the chance to opt in or out.

Amazon says it employs encryption and related techniques so that owners of Sidewalk bridges "have no idea what types of endpoints are connected, times in which they are connected, or information about the owner of the endpoint." These gateways can't inspect packets between endpoints in the mesh and Amazon's back-end servers. Similarly, we're told, endpoints can't discern information about the gateways they are using.

There are more technical details on the design of the cryptography involved in the above PDF.

We're told Sidewalk will only sip your internet connection rather than hog it, limiting itself to half a gigabyte a month. This policy appears to live in hope that people aren't on stingy monthly data caps.

"The maximum bandwidth of a Sidewalk bridge to the Sidewalk server is 80Kbps, which is about 1/40th of the bandwidth used to stream a typical high definition video," Amazon claimed.

"Today, when you share your bridge’s connection with Sidewalk, total monthly data used by Sidewalk, per account, is capped at 500MB, which is equivalent to streaming about 10 minutes of high definition video."

US not UK at launch

Amazon sent out emails this week to folks in the United States, alerting them to a launch of Sidewalk expected this year. Confusingly, some people in the UK got the messages, too, though Amazon has stressed the service will kick off solely in America first. Software updates switching on the functionality will be rolled out, and it's up to you to read the email and opt out. One way to do that is to open your Amazon Alexa app and disable Sidewalk from the account settings screen.

We previously wrote about Sidewalk in September, and noted that, opt-outs aside, the idea behind it – community-sized resilient meshes of devices – wasn't necessarily a bad one.

Just don't forget that Ring and the police, in the US at least, have a rather cosy relationship. While Amazon stresses that Ring owners are in control of the footage recorded by their camera-fitted doorbells, homeowners are often pressured into turning their equipment into surveillance systems for the cops. ®