且看绑定的定义：Binding is a mechanism to control the flow of messages from one application to another application (or multiple applications). The binding mechanism is implemented in all devices and is called source binding.
简单理解：绑定为控制信息在应用之间流通的一种机制。注意一点： from one application to another application (or multiple applications).注意这里定义为应用于应用之间，而不一定是设备与设备之间，那么在同一个设备上不同应用之间也是可以流通的。比如一个设备上有一个开关的应用和一个灯的应用，那么着两者之间是可以相互绑定的。
Binding allows an application to send a packet without knowing the destination address, the APS layer determines the destination address from its binding table, and then forwards the message on to the destination application (or multiple applications) or group.
这里和上一篇文章中讲的AddrNotPresent地址模式有着莫大的关系，两者相互帮助。