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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 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). SGs is a stateless 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.

As with all dsTest products, the node configurations and test scenarios are easily defined and configured with XML files that are validated against a published XML Schema to avoid invalid definitions. With our dsClient GUI, you can create, run, and archive tests, capture, graph and archive operational measurements, capture real-time data flows, and manage your dsTest servers and testing scenarios with a standalone application that runs on your PC.

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 testing solutions.

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.

Advanced Testing Features

SmartEvents — Alter application behavior or coordinate multiple interface applications with SmartEvents. Our programmable, subscriber-level state machine gives you the ability to define handlers for specified application events that can then cause an event in another application to be executed. You can also configure handlers to modify subscriber information during run-time, introduce timers, or randomize subscriber behavior based on configurable probabilities to name a few of the many options in one of dsTest’s most powerful features.

SmartMessageElement — Insert, delete, or replace elements in Diameter, RADIUS, MAP, LDAP, GTP, REST, or SOAP messages with our SmartMessageElement solution. Define proprietary signaling or corrupt elements to facilitate negative testing. You can specify when your elements are used with SmartEvents.

Traffic Profile — Draw the shape of your test actions across time with Traffic Profile. You can define the rate for any action as a static rate or reference a Traffic Profile configuration, which also means that multiple Traffic Profiles can be running currently. Use Traffic Profile in conjunction with the randomizing features in SmartEvents to design a test that more truly simulates real-world network activity.

Operational Measurements

dsTest provides rich sets of measurements for the SGs interface:

  • 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 SGs measurements and socket measurements.

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

Supporting Standards