Gateway: any point where information passes through devices on an IoT network. So it can be virtual software or real hardware such as a router.
Is a router or some software that allows two or more independent networks with different protocols to communicate with each other. For example, it allows a node from a local area network (LAN) to reach the World Wide Web.
It converts the protocols of one type of physical environment into another. That allows incompatible networks with different protocols to communicate and transfer data between them.
