---

---

IMS was originally defined by an industry forum called 3G.IP, formed in 1999. 3G.IP developed the initial IMS architecture,

---

Posted by waqasahmad

• An Application layer consisting of Application Servers
(AS) that host the IMS services and a Home Subscriber
Server (HSS),
• A Control layer made of several service subsystems
among which the IMS core
• A Transport layer consisting of the user equipment (UE),
Access Network, Next Generation Network (NGN) core,
NASS and RACS .

---

Posted by Dingbang