Introduction to SMPP

Introduction

SMPP stands for Short Message Peer to Peer. It is a communication protocol used to send SMS messages directly to an SMSC over the internet. An SMSC, or Short Message Service Center, is a system that handles or routes SMS messages. An SMSC can be an SMS provider or an aggregator service. An aggregator routes SMS messages to different providers and offers a way for businesses to connect to them.

The SMPP protocol is mostly used for large volumes. If you are a small business sending or receiving more than about 500 SMS per month, SMPP is likely to be the most economical way to send SMS.

You can find a list of current SMPP SMS providers here.

Competing technologies

Two other technologies compete with SMPP:

• The GSM modem. This is a good option for low to medium SMS volumes.
• HTTP. This is another option for sending large volumes, but there is no standard and receiving messages usually requires setting up your own server.

The SMPP protocol is usually the preferred method because of its speed, reliability, and full support for the SMS feature set.

Security (TLS)

In recent years, most SMPP providers and SMPP client libraries, such as Auron Omni and the SMS Component, support TLS.

TLS, or Transport Layer Security, is a security protocol used to secure many well known internet protocols such as HTTP, SMTP, and IMAP.

Before TLS became the standard for securing SMPP connections, most providers used a combination of VPNs (Virtual Private Networks) and IP whitelisting. IP whitelisting ensured that only known IP addresses could connect to the SMSC. The VPN created a private network between you and the provider that is isolated from the rest of the internet.

Specification

SMPP is a standard protocol. The standard has three versions:

• Version 3.3 This is the first version that saw widespread use.
• Version 3.4 This is the most common version of SMPP. It adds extensibility through TLVs (Tag Length Value) to support custom data in SMPP packets.
• Version 5.0 This version adds more advanced throttling options. It is not commonly used.

You can find the full SMPP 3.4 specification here.