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dsTest, Developing Solutions, SGs Interface, MME, VLR, MSC

dsTest supports server emulation and client simulation capabilities for Short Message Service (SMS) on the 3GPP TS 29.118 (SGsAP) SGs interface.  Test MME SGs interfaces in 4G and LTE networks with our Visitor Location Register Emulator/SMS Message Service Center.  Use the SGs Interface application to test the capacity and performance of a VLR/MSC in support of Circuit-Switched Fallback in the Evolved Packet System (EPS).  dsTest provides more tools for LTE testing.  SGs is a stateless protocol.

A rich set of operational measurements is collected at specified intervals and stored in a SQLite database on the dsTest server.  Real-time measurements may be retrieved through our dsClient CLI interface or graphed via our dsClient GUI interface.


The SGs application implements the following SGsAP procedures when associations between a UE and an MME and/or VLR have been established:

  • Paging for non-EPS Services;
  • Location Update for Non-EPS Services;
  • Non-EPS Alert;
  • Explicit IMSI Detach from EPS Services;
  • Explicit IMSI Detach from Non-EPS Services;
  • Implicit IMSI Detach from Non-EPS services;
  • VLR Failure;
  • MME Failure;
  • MM Information;
  • Tunneling of NAS Messages;
  • Service Request.

A complete set of events that can be generated with the SGs interface application can be found here.

MME Testing (Server Emulation)dsTest, Developing Solutions, SGs Interface, VLR Emulation, MSC Emulator, MME Testing

The VLR emulator participates in the MME-initiated procedures such as Location Updates or Detaches when indicated, eliminating the need to dedicate a production server to lab activities.  You can manually trigger VLR-initiated procedures, Paging or Non-EPS Alert for example, by executing a test event chain with a run-time command or during an automated test.

Read more about out VLR Emulator.
Read more about SMS configurations.

VLR/MSC Testing (Client Simulation)

The SGs Interface application can be used to simulate an MME’s SGs interface to determine the impact of new VLR features and standardsdsTest, Developing Solutions, SGs Interface, VLR Testing, MSC Testing, MME Simulation before they are deployed in a network.  The SGs Interface application allows you to validate VLR performance and capacity in a realistic network environment, replicating the deployment configuration.

Execute timed chains of test events with a run-time command or during an automated test to attach or detach specified subscribers and initiate MO short messages, simulating real-world subscriber activity.

Multiple MME nodes can be instantiated on a single server, each with scalable subscriber loads and transaction rates.  In this mode, up to 1000 independent MME nodes may be simultaneously simulated and MME-MME mobility may be simulated.  The nodes are fully independent and their subscriber configurations may be independent, overlap, or be duplicated.

Supporting Standards