IMS is a whole new way to deliver multimedia (voice, video, data, etc.) regardless of the device (mobile phone, landline phone, cable, Internet, etc.) or the access medium (cellular, WiFi, Broadband, fixed-line, etc.).
In today's busy schedule we want to save our e.g. Whenever we browse internet we want to same settings on all devices either my desktop(home/office), my smartphone or laptop. for that we can use crome browser which sync all your activity (your browsing cache, saved passwords etc.) with your account irrespective of device you used to do so.
Similarly to provide multiple services at a time (voice, data, video) on your device, IMS architecture have been designed. Multiple roles of each different devices (landline, cellular phone, Digital Tv/IP Tv) will compact to a single device. You will have option to choose your device behaviour, all your registered IMS compliant devices will behave in your desired way. You as end user will have to choose your operator on basis of services provided. The IMS-compliant devices will be more capable of handling multimedia reducing the need for different devices to handle different types of media (voice, video, and data). In addition, one device could easily take the place of multiple devices. your phone is your mobile when you leave home and join the cellular network, but becomes your home phone when you are in the house using WiFi, and even becoming your office desk phone when you enter your place of employment.
You can enjoy data, voice, video simultaneously using different access network (e.g. the ability of a mobile cellular phone to switch to WiFi VoIP — mid-call — when it discovers a valid network to use. In this scenario, your mobile phone would dynamically move your existing call over the cellular network to a valid WiFi network (for example, your home wireless network) when you came into range, saving your cellular airtime and providing additional bandwidth for data communications. If you had IMS-enabled phones attached to your landline carrier, you could transfer a call from your IMS-enabled cellular phone to your home phone or VoIP soft-phone on your laptop while travelling, transferring the call across service providers without dropping it).
