Call Session Control Function

Ericsson Call Session Control Function (CSCF) is at the heart of the IP Multimedia Subsystem (IMS). It manages all signaling from end-user to services and other networks, and builds a horizontal layer that allows for the convergence of different access networks.

The cornerstone of the service delivery system must possess superior carrier grade characteristics, coupled with uniform multimedia handling for all types of accesses.

The product controls the fixed and mobile IMS when moving to a fully converged telecommunications network. It comprises of all the functional modules required to manage signaling from end-user equipment, allocating application servers, establishing emergency connections and controlling the communication with other networks.

Ericsson Call Session Control Function:

  • support service and network convergence meaning that several services over multiple access technologies (fixed/mobile convergence) can be handled by the same CSCF product
  • standard compliant, and in addition a lot of flexibility has been incorporated to overcome potential interoperability challenges
  • part of the majority of the current VoLTE deployments
  • support fixed voice, mobile voice,  enterprise communication, Rich Communication Services (RCS), Wi-Fi calling

CSCF can be deployed on traditional telecom optimized hardware as well as in virtualized deployments based upon 3rd party hypervisors and 3rd party HW, or OpenStack based Ericsson Cloud System, which gives smoother deployment and improved TCO.


Proven product

Ericsson is selected supplier for virtualized IMS functions with several Tier 1 operators, and CSCF is live at several customers in a virtualized environment.

In commercial operation since 2005 it’s the World’s most widely deployed and reliable CSCF (providing higher than 99.999 percent availability). It features the most field-tested interoperability with standard and non-standard interfaces, terminals and legacy networks.

Feature richness

The Ericsson Call Session Control Function offers:

  • seamless migration from circuit switch to IP based IMS networks and is common for wireline and wireless domains
  • flexibility in supporting a variety of network scenarios and services
  • supports a wide variety of security authentication procedure
  • provides high availability a robustness with Automatic software recovery, Data replication, Overload protection and failover mechanism,  On-line backup and Software updates
  • flexible charging mechanisms to support many different charging models including post-paid, pre-paid, based on volume, time, per event.

Flexible deployment alternatives

Ericsson CSCF provides flexible deployment alternatives and it is certified with different hypervisors. It is also possible to start with small system and increase the capacity as the traffic in the solution increases.