SMSC Simulator

Melrose Labs operates SMSC simulators (aka SMPP server simulators) for use in the development and testing of SMS text messaging capabilities within applications. They simulate SMSCs (short message service centres) and SMPP SMS gateways, with support for SMPP v3.3, SMPP v3.4 and SMPP v5, using TLS and non-TLS connections. Our SMSC simulators are also part of Melrose Labs SMPP Implementation Testing that includes testing (load testing, SMPP bind type/version support) of SMPP servers, SMS gateways and SMSCs.

The simulators can be used to test the MT SMS (to mobiles) and MO SMS (from mobiles) operation of an application. Applications send SMS messages to mobiles by submitting messages to the SMSC Simulator service using SMPP. The SMSC simulators simulate the delivery of the messages, including the generation of delivery receipts back to the application. SMS messages from mobile numbers can also be submitted and delivered to the SMS application (see Simulate Inbound SMS to your Application).

The advantage of the SMSC simulators is that you can send SMS messages from your application without messages being delivered to real mobile phones and therefore without any SMS delivery costs. Stress testing of your application can also be performed to show how your application behaves under load and various other scenarios tested before live operation and without affecting production SMSCs. The SMSC simulators can handle high rates of SMS and a high number of simultaneous connections from your application.

Using the SMSC Simulator service

The SMSC Simulator service is publicly available and connection details dedicated to individual users are provided (see below for your SMPP account details). SMPP over TLS support is available for SMS applications to connect securely (SMPP TLS port: 8775).

SMS Text Simulator: Simulate Inbound SMS to your Application

To simulate MO SMS (i.e. inbound SMS or person-to-application SMS) from a mobile to your application, you can either (a) use an SMPP TX bind to submit the MO message to the simulator or (b) use the above Inbound MO SMS Tool.

In either case, you would submit a message using the above SMPP account details to a destination_address that contains the digits of your system ID. By including the digits of your system ID in the destination_address, the message will be routed by the simulator to your application. The destination_address field must be at least 8 digits in length so ensure that you prepend or append at least two digits to your system ID, otherwise the simulator will reject the submission.

The simulator also supports the use of schedule_delivery_time in the submit_sm and this can be used to schedule delivery of MT and MO SMS.

SMPP operations supported by the simulators

SMSC simulators last updated 9 July 2020

We are working to ensure that our simulators allow you to test most, if not all, aspects of SMPP applications such as applications with SMS support and SMS infrastructure. Operations currently supported by the simulators are shown below. Further operations will be provided in future and frequent updates.

• Session Management:
  • bind_receiver/resp - Used for receiving delivery receipts.
  • bind_transmitter/resp - Used for submitting messages.
  • bind_transceiver/resp - Supported for v3.4 and v5, and used for submitting messages and receiving delivery receipts.
  • unbind/resp - ESME unbinding from SMSC and SMSC issues unbind_resp. SMSC unbinding from ESME when ESME unresponsive.
  • enquire_link/resp - Will respond to enquire_link from ESME and will issue enquire_link to ESME every 120s of inactivity.
• Message Submission:
  • submit_sm/resp - Will issue positive response with message_id of 8 characters in length for v3.3 and 64 characters for v3.4 and v5. Will issue error response (ESME_INVDSTADR/0x0000000B) if destination_address less than 8 characters in length.
• Message Delivery:
  • deliver_sm/resp - Delivery receipts sent to ESME on receiver binds (SMPP v3.3, 3.4 and v5) and transceiver binds (SMPP v3.4 and v5 only). deliver_sm short_message field with textual receipt plus TLVs containing message ID (i.e. receipted_message_id), status of message (i.e. message_state with value of 2 for DELIVERED) and error (i.e. network_error_code with value of zero indicating no error)

Melrose Labs SMSC Simulator Abbreviated SMPP PICS

SMSC Simulator Abbreviated SMPP Protocol Implementation Conformance Statement (SMPP PICS)

Operations Supported

Notes on using the SMSC Simulator service

1. SMPP (Short Message Peer-to-Peer) protocol must be used to connect to the simulator.
2. Use SMPP v3.3, v3.4 or v5 and specify the version in the bind request.
3. Bind using one or more transmitter (TX), receiver (RX) or transceiver (TRX) binds.
4. Use transceiver (TRX) or receiver (RX) binds to receive delivery receipts.
5. If a delivery receipt has been requested for a message, a receipt will be returned to your application in 3-12 seconds (random) after the submit_sm_resp. If there is no existing TRX or RX bind, then the receipt may be discarded.
6. Mobile numbers (MSISDNs) should be in international format.
7. TLS 1.1 and up are supported for SMPP sessions. SSL and TLS 1.0 are not supported for connections.

If you wish to perform testing using production SMSCs for delivery to mobiles, then we recommend that you use the Tyr SMS Gateway service. To receive MO SMS from mobiles take a look at Melrose Labs Tyr SMS Gateway.

Source code for earlier versions of ourdb SMSC simulator can be found in the Melrose Labs GitHub repository at smpp-smsc-simulator.

For production SMSCs and SMS gateways we suggest you take a look at the following:

• Tyr SMS Gateway
• SMPP SMS Gateway (operate your own SMS gateway)
• SS7 SMSC (operate your own SMSC)