Today almost every home and small home office has a home network, and an Internet connection.
The current home network enables multiple devices e.g. PCs,tablets etc to connect to each other, and also to connect to the internet.
Today most home networks will use a mixture of Ethernet and Wi-fi wireless networking technology and the TCP/IP networking protocol.
Smart Home devices will connect either directly to the existing home network or else indirectly via a hub or gateway.( Zwave and Zigbee).