What IsSMPP?

SMPP (Short Message Peer-to-Peer) is a protocol the telecommunications industry uses to exchange SMS texts over the internet.

The exchange mainly takes place between Short Message Service Centers (SMSCs). Being a level-7 TCP/IP protocol, SMPP enables the speedy delivery of text messages.

The system serves as a language for cellular networks to transmit SMS communications. It controls how External Short Message Entities (ESMEs), like business messaging platforms and Internet of Things devices, communicate through mobile phones.

The Different Versions 

There are three various versions of SMPP: v3.3, v3.4, and v5.0. The oldest version is SMPP v3.3. Newer versions include new types of sessions, new PDU (Protocol Data Unit) parameters, and support for extra technologies. Each session must specify the version the ESME uses, as it determines the interaction between the two entities.

How Does It Work?

When a mobile phone or SMS-enabled application needs to deliver a text to another device, it activates an SMPP session. The session takes place via the mobile carrier’s message service center (SMSC). While the session is in process, the two endpoints communicate via the SMSC, which defines which entity is relaying the messages.

It also determines whether to accept or reject the transmission. As an element of intelligent routing, it allows for dynamic routing decisions according to real-time network conditions and delivery needs.

Should one of the entities require an SMS gateway to communicate, the gateway serves as a mediator, too. It transmits data to and from the SMSC. If the Message Center rejects the transmission, it sends an error code to specify the issue. This can be an invalid request, destination, message ID, or text length.

Mobile network operators sometimes use SMPP in conjunction with SIP trunking to enable businesses to send messages over IP networks. This facilitates the integration of SMS with VoIP (Voice over Internet Protocol) systems.

Types of Sessions

There are three different types of sessions that an ESME initiates. A transmitter session is for sending mobile terminated messages to a mobile device. Receiver sessions are those that ESMEs activate to receive mobile-originated messages.

As for transceiver sessions, they support both sending and receiving messages. This type of session isn’t available with v3.3. An outbind session, on the other hand, is one that the SMSC initiates.

Protocol Data Unit

At the beginning of each session, a bind command defines what type of interaction will occur. To activate a transmitter session, for example, the SMSC delivers a PDU containing the command bind_transmitter. This PDU, which consists of requests and responses, also includes the ESME’s type, passcode, and identification. Moreover, the PDU specifies the SMPP version that the ESME is utilizing and determines where the SMS communication is coming from.

Benefits of SMPP

  • Efficiency: Designed with high performance in mind, SMPP allows for the fast transmission of SMS messages

  • Reliability: By providing delivery confirmation and solid handling of errors, it guarantees that messages reach their intended destination

  • Scalability: An SMPP server can handle messages in large volumes, making it ideal for companies with considerable messaging needs

  • Real-time communication: It facilitates real-time reporting and delivery of messages, which is vital for time-sensitive communication

  • Security: It offers secure messaging, safeguarding sensitive information during delivery

  • Customization: Users can configure the system to fit certain requirements, making it versatile for different messaging software

What Is It Used for?

Business Messaging

Businesses use an SMPP protocol to deliver messages from an SMS platform to individual contacts or a whole group of customers. These include promotional messages, customer support, appointment reminders, feedback requests, and OTP verification.

Cellular IoT 

IoT (Internet of Things) devices like smart thermostats, smoke alarms, and home security systems use SMPP to transmit notifications. These can be about energy consumption, motion detection, or other critical alerts. When a smart alarm system detects a fire, for example, it uses the SMPP to immediately inform the homeowner. The alert can sometimes include a link to the smart security camera.