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dsTest, Developing Solutions, Gs Interface, Subscriber Management

dsTest supports both server emulation and client simulation capabilities for the Base Station subsystem Application Part (BSSAP) Gs interface. Test Serving GPRS Support Node (SGSN) Gs interfaces in UMTS or LTE networks with our Visitor Location Register (VLR) Emulator. Use the Gs Interface application on our SSGN node to test the capacity and performance of a VLR. For more information regarding how to use dsTest for BSSAP+ functional and compliance testing, see our page on Conformance Testing.


The Gs Interface application implements the following BSSAP+ procedures when associations between an SGSN and a VLR have been established:

  • Paging for non-GPRS Services;
  • Location Update for Non-GPRS Services;
  • Non-GPRS Alert;
  • Explicit IMSI Detach from GPRS Services;
  • Explicit IMSI Detach from Non-GPRS Services;
  • Implicit IMSI Detach from Non-GPRS Services;
  • VLR Failure;
  • SGSN Failure;
  • MS Information.

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

SGSN Testing (Server Emulation)dsTest, Developing Solutions, Gs Interface, Gs Server Emulation, SGSN Testing, Subscriber Management

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

Read more about our VLR Emulator.

VLR Testing (Client Simulation)

The Gs Interface application simulates an SGSN’s Gs interface to determine the impact of new VLR features and standards before they are deployed in a network. The Gs Interface application allows you to validate VLR performance and capacity in a realistic network environment, replicating the deployment configuration.dsTest, Developing Solutions, Gs Interface, Gs Client Simulation, VLR Testing

Execute timed chains of test events with a run-time command or during an automated test to trigger client-initiated procedures.

  • Start and stop specified subscriber sessions, simulating real-world subscriber activity
  • SGSN failures

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

Operational Measurements

dsTest provides rich sets of measurements that include but are not limited to:

  • Transaction and transport layer attempts, successes, and failures
  • Transaction duration, transactions-per-second, and round-trip delay
  • Message and byte counters
  • Errors encountered and error indications received in messages

See our Online Help for Gs measurements, SCCP measurements, M3UA measurements, and SCTP measurements.

You can read more about the reporting features offered with dsTest and dsClient here.

Supporting Standards