IP Multimedia Subsystem (IMS) is a system that enables people to use the internet and different types of multimedia services like voice, video and data on their phones or other devices. It uses the internet to allow you to have conversations, access information, and use other kinds of media like photos, music and videos. IMS also makes it easier for the different kinds of services to work together, so that all kinds of devices can connect with each other. For example, if you have a phone and a computer, they both can access the same information over the internet, and they can both talk to each other.