Building Wireless Sensor Networks

Chapter 7. Over the Borders

ZigBee is only one of the great flavors of networking. In this chapter we learn to make gateways that cross borders to connect with neighboring networks, including a remarkably easy path to the Internet. You’ll see full examples, showing how to allow anything to talk to everything everywhere; plus there’s something special for you starry-eyed celebrity fans. Let this chapter be your passport.

Gateways

The great thing about standards is there are so many of them. Bluetooth, IPv6, UDP, ZigBee, SMS, VoIP, WiFi, Ethernet, 4G, SMTP, and TCP/IP all define different networking protocols and layers within those protocols. There’s no such thing as a perfect network; that’s why there are so many different ways to get networking done. Each protocol is designed to solve a specific type of problem. Most do a great job at their task. For example, Bluetooth performs solidly when connecting up eight local devices as a personal area network. At the same time, many of the engineering choices that solve one kind of problem create barriers when the protocol is pushed into unfamiliar territory. Bluetooth’s simple pairing and addressing schemes don’t readily scale to networks of hundreds or thousands of nodes, while other protocols may sacrifice such simplicity for flexibility and scalability. Luckily, there’s no need to stick to a single protocol. Each can do what it’s best at, and connections can be made so they all work well together. Using the best network means using many ...