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S3 Interface, dsTest, Developing Solutions, MMe, SGSN, GTP, LTE Testing, EPC Testing


dsTest supports the GPRS Tunneling Protocol Version 2 for Control plane (GTPv2-C) message sets over the Evolved Packet Core (EPC) signaling interface S3.  S3 is a GTP signaling-only interface, used between the Serving GPRS Support Node (SGSN) and the Mobility Management Entities (MME) to support inter-system mobility.   With the dsTest S3 Interface application, you can test GTP-C initiators (SGSNs), and verify responses from responders (MMEs).

The S3 interface is between SGSNs enhanced to support EPS mobility, and MMEs in order to support handover to/from 2G/3G radio access network for 3GPP accesses. The functions supported include transfer of information relating to the terminal that is being handed over and handover/relocation messages.

The S3 Interface Application, along with other dsTest interface applications provide dsTest users with complete EPC testing capability.  Our eNodeB, MME, SGW, PGW, and Home Subscriber Server (HSS) emulators support end-to-end testing of IP connectivity to LTE access.  dsTest maintains a comprehensive set of Operational Measurements for the S3 interface.


The S3 Interface Application initiates the following Mobility Management events from a Simulated SGSN node:

  • Identification Request/Response
  • Context Request/Response
  • Forward Relocation Request/Response
  • Forward Relocation Complete Notification/Acknowledge
  • Relocation Cancel Request/Response
  • Detach Notification

A complete set of events that can be generated with the S3 interface application can be found here, and our GTPv2 Dictionary can be used to help construct, test, and interpret the results of your S3 testing.

MME Testing (GTP-C Initiator Simulation – SGSN)

Verify the reaction of your MMEs to UE mobility by simulating a SGSN.  Verify you’re your MME responds, or acknowledgments, correctly to:

  • Identity requests when a UE has moved to a different SGSN;
  • Bearer context information requests for the UE as a part of TAU/RAU procedure and UTRAN/GERAN to E-UTRAN/UTRAN (HSPA) SRVCC procedure;
  • Relocation requests as part of Inter-RAT handover and other relocation procedures;
  • Forward Relocation Complete Notification messages, indicating a handover has been successfully finished;
  • Relocation cancel requests as part of the Inter RAT handover cancel procedure;
  • Detach notifications as a part of detach procedure if the Idle mode Signaling Reduction (ISR) is activated between the MME and SGSN for the UE.

Your S3 SmartEvents state machine provides the ability to create S3 GTPv2-C message flows and use them in combination with Policy and Charging Control (PCC) interface applications to test gateway elements in the mobile packet core.  Use the S3 Interface Application and our SmartEvents feature with other interface applications to trigger network-initiated events from our Emulators and validate the resulting GTP-C and Diameter signaling.

Test your MME performance by initiating context requests, detach notifications, and relocation requests from a simulated SGSN in volume.

Read more about network testing.
Read about our EPC Node Emulators.
Read about our other GTP Interface Applications.

SGSN Testing (GTP-C Responder Simulation – MME)

Simulate GTPv2-C interfaces to your SGSN GTP-C initiator.  Verify that the initiator correctly interprets the S3 responses.  Test the capacity and performance of your SGSN with other dsTest interface applications to trigger network-initiated events and validate the resulting signaling and user plane traffic.

Advanced Testing

Using our SmartEvents application, you have the ability to create simple to complex transaction flow state machines for the S3 interface.  You can construct different paths for success, failure, or other conditions, all well defined within the state machine.  Using our SmartAVP feature, you can create and customize the incoming and outgoing S3 messages increase the flexibility of your test scenarios.  Multiple handlers can be used with different templates of the same message type in order to execute various actions or state changes depending on the composition of a received message.

Read more about GTP functional and compliance testing with dsTest.

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 GUI application that runs on your PC.

Supporting StandardsS3 Interface, S3 Testing, GTP Testing, MME Testing, SGSN Testing, dsTest, Developing Solutions