Terms and definitions in messaging

Multichannel messaging service is based on a variety of telecommunication and Internet technologies. In the description of services, we often use abbreviations that may not always be known to you. Here we have compiled a glossary of terms and definitions used in the industry.


Stands for "Protocol Data Unit". A PDU is a specific block of information transferred over a network. It is often used in reference to the OSI model, since it describes the different types of data that are transferred from each layer.

As per the SMPP specification, each PDU has a mandatory header section that is the same for each PDU transmitted between ESME and SMSC.