Smart Home is an umbrella term used to cover an ever-growing array of connected devices. By connected we mean that they form part of your home network and therefore communication with these smart devices is via your router - whether connected physically by Ethernet cable or wirelessly. The concept of a smart home is to add convenience to life in general, either by providing automation for heating or lighting systems or to deliver additional functionality such as security when using cameras or alarms.
The essence of a smart home is control - the ability to operate devices remotely when you’re not at home or to set routines to automate functions for convenience for security. In order to enable this capability devices must be able to see the device that will control them - in most cases a smart phone or tablet connected to the same network. Therefore, all smart devices must be connected to the router within the home.