The R-IM-SSF is a protocol translator that mediates between a CAP or INAP session with the SIS and a SIP session with an external SIP application server.

R-IM-SSF module features

The table below outlines the features of the R-IM-SSF.

Feature supported Description


Supports GSM CAP v1, v2, and v3; ETSI INAP CS1; Ericsson INAP CS1 (optional); and Ericsson INAP CS1+ (optional).

Tip A version of R-IM-SSF that supports other proprietary vendor variants of INAP is available on request. Please contact your OpenCloud sales representative for more information.

Call Control

Supports messages such as InitialDP, RequestReportBCSM, EventReport, Connect, Continue

Multiple Trigger Types

Supports triggering from the IN with InitialDP and from the SIP network with INVITE (network initiated call).

User Interaction

Supports playing announcements by mapping an INVITE from the SIP application server (with a special prefix or a play-url) to Tone or Message announcements provided by a node in the IN. The R-IM-SSF can use direct or assisting modes for user interaction.

Customisation options for SIP

There are a number of options that allow the makeup of the SIP signalling to the SIP application server. The operator can influence the headers includes in the SIP INVITE and the makeup of the SDP portion.

R-IM-SSF in action

The R-IM-SSF module provides support for protocol translation from INAP and CAP to SIP. The R-IM-SSF processes a call by acting as a B2BUA to the SIP-AS and by acting as an SCP to the SIS. The R-IM-SSF is invoked by a SIS composition, which may include other IN services to run. For example, in the following diagram we see that a service composition is using the R-IM-SSF to run SIP-based VPN services, in a composition with an IN-based OCS.

Previous page Next page