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IMS VoLTE Testing

dsTest, Developing Solutions, IMS VoLTE Testing, Voice over LTE, 3GPP, IMS Testing, CSCF Testing

The protocols and interfaces for delivering Voice over LTE (VoLTE) services are complex, but dsTest simplifies the tasks of compliance and measuring performance of Evolved Packet Core (EPC) and  IP Multimedia Subsystem (IMS) networks.  The dsTest platform includes advanced features available to easily configure, test, and quantify the performance of  network equipment and services, including IMS VoLTE and the IMS Core Network.

The Session Initiation Protocol (SIP)/Real-time Transport Protocol (RTP) Interface Application  is one of the 3GPP signaling protocols, utilizing the Session Description Protocol (SDP), and is a part of the IP Multimedia Subsystem (IMS) architecture.  Besides SIP, dsTest supports IMS interfaces such as Rx, Cx/Dx, Sh/Dh, Ro/Gy, and Rf/Gz, and EPC Core interfaces that allow end-to-end testing capabilities in 3G/4G/5G packet core networks.

dsTest can emulate a PGW and P-CSCF to simulate VoLTE subscriber activity, initiating procedures with a PCRF over the Gx and Rx interfaces.  In addition, dsTest hosts an SPR that provides subscriber information to the PCRF, over the Sp interface, and to the emulated PGW and CSCF.   The shared subscriber database enables the PCRF to be provisioned with the same profiles that supply the emulated PGW and CSCF with subscriber identities, service definitions, custom AVPs, and the SmartEvents that define the desired message/call flow.  Using a common repository keeps configured and dynamic subscriber information synchronized across all devices and applications.

VoLTE call flows can be simulated by setting probability assignments for the number of subscribers that will place voice calls, and traffic load profiles can be created that produce the desired volume of simulated voice traffic transactions, thereby triggering the appropriate procedures that would establish dedicated bearers for the traffic.  Thus you can shape the aggregate load profiles while randomizing the actions taken by a particular subscriber, resulting in a more realistic simulation of subscriber activities.

In more complex testing scenarios, this type of traffic load profile would be useful in testing all nodes involved with the VoLTE call flow, including the PCRF, HSS, OCS, OFCS, MME, PGW, PCEF, and CTF.  Along with VoLTE call flow testing, the inclusion of a DRA can test the Diameter signaling routing in the simulation.

Developing Solutions has showcased a VoLTE environment at GSMA’s Mobile World Congress and other industry forums.  This environment simulates the wide range of Diameter transactions and interfaces required to support VoLTE calls, including verification of routing of dynamic policy and charging transactions between many core EPC elements.

Advanced Diameter Testing Features

dsTest provides tools to enhance your testing:

  • Insert, delete, or replace AVPs in your messages with our SmartAVP solution.  SmartAVP enables you to define proprietary signaling or to corrupt AVPs to facilitate negative testing.
  • Configure commands to define the series of actions and rates that each subscriber takes. Advanced profiles can be created using SmartEvents to define a mix of traffic based on probability assignments.  With SmartEvents, you can specify when your SmartAVPs are used.
  • Define a set of message templates against which all messages will be validated with our Diameter Dictionary.  Every Diameter message is validated, even under load conditions.

Read more about our SmartEvents feature.
Read more about our Advanced Testing Features.