The Internet of Things (IoT) — which links mobile devices, wearables, smart appliances, connected cars, and other gadgets to the cloud and each other — is expected to expand considerably over the next few years. Cisco (NASDAQ: CSCO) estimates that the number of connected devices will double from 25 billion in 2015 to 50 billion in 2020, and IDC estimates that the entire IoT market will grow from $655.8 million in 2014 to $1.7 trillion in 2020.