SIP-Trunked IVR (N2SRP)

IVR for CAMEL/INAP, VXML, or Scripting

The N-Squared Specialized Resource Platform (N2SRP) is a specific deployment model of our flexible SIP component architecture. It uses SIP-trunking for voice channel interaction, and call control is sourced from external service nodes - either INAP/CAP Service Control Points (SCPs), or VoiceXML document servers.

When deployed in this model, the following scope applies:

  • N2SRP SIP sessions are single-leg between a single subscriber (A-Leg) and N2SRP (B-Leg).
  • N2SRP may originate and/or terminate RTP audio, but will never relay or transcode RTP.
  • N2SRP has no local service logic (and hence no service design tool). Call flow control is determined by the INAP SRF interaction model, or from VoiceXML documents executed by the N2SRP VoiceXML interpreter.
  • N2SRP has no subscriber database. Audio file data is stored in either a database, or on disk.
  • N2SRP, when executing a VoiceXML interpreter session, may transfer a call to another destination number.


The N2SRP is compatible with:

  1. Any CAMEL or INAP Service Control Platform, such as the Service Logic Controller (SLC) node from Oracle Communications Network Charging and Control (OCNCC) or Convergent Charging Controller (OC3C) product, or other third-party SCP platforms.
  2. Any HTTP server capable of serving VoiceXML 2.0 or 2.1 documents to be interpreted by the N2SRP.


Product Information

User & Technical Guide

Protocol Conformance Statements

Deployment Notes

Platform Sizing

The N-Squared Specialized Resource Platform is a great fit for operators of any size needing a cost-effective, off-the-shelf, standards-based INAP-Controlled or VoiceXML-Controlled IVR. It is ideal for deployments from 50 up to 15,000 simultaneous voice channels.

The solution is laterally scalable with N+1 deployment for High-Availability, Geographic Redundancy, and to support increased traffic growth.

OSS/BSS Features

N2SRP has Administration GUIs for audio file management and platform monitoring. Standard Operational features include Alarms, Statistics, and Event Data Records.

The SRP generates Event Data Records including:

  • SIP EDRs describing the SIP voice trunk interaction.
  • INAP EDRs describing the INAP call control interaction.
  • VoiceXML Interaction EDRs detailing the interactions that occur during VoiceXML controlled calls.

N2SVCD Components

The N2SRP is built on the N2SVCD framework. The following diagram shows the N2SVCD components which are deployed for N2SRP in INAP SRP controlled mode:

When deployed with VoiceXML control, the N2SVCD deployment is similar:

More information is avialable in the N2SIP technical guide’s deployment subsection.

Telco Products