IP Multimedia
Subsystem
IP Multimedia
Subsystem
The IP Multimedia subsystem (IMS) architectural blueprint identifies a number of capabilities at the telecommunications network service layer. The main ones are:
- SIP Application Server
- Service Capability Interaction Manager (IMS SCIM)
- Service Switching Function (IM-SSF)
These and their relationship with the core IMS network capabilities are illustrated in the diagram below.
In addition to the IM-SSF identified in the IMS specifications, a strong case can be made for the reverse capability (Reverse IM-SSF). This protocol gateway gives TDM IN subscribers (the vast majority currently) access to the applications and services hosted on the IMS/ SIP Application Server. This means that new applications and services can be made available to a substantially larger subscriber base when they are launched. Complementing this, the IM-SSF anchors calls and sessions in the IMS domain for IMS subscribers and gives access to applications and services that are hosted in the TDM/ IN domain. This means network operators do not need to port all applications and services to IMS to present a comparable service offer for IMS to the market.
For both IM-SSF and R-IM-SSF, the TDM protocols can be standard CAMEL protocols, INAP CS1-based protocols or WIN protocols.
Rhino can be used to implement additional service layer network functions due to its inherent multi-protocol capabilities, such as:
- IP-Centrex
- Presence Servers
- IP-PBX
- Instant Messaging to SMS/ MMS gateways
- A generic “Push Server” for pushing information (content, ring-tones, video clips, news etc)
- Push-to-talk
- Voice Call Continuity (VCC)
- Multi-party Conferencing etc.
- Directory Services
- Policy Server
- Peer-to-peer sharing