Short Message Peer-to-Peer

The Short Message Peer-to-Peer (SMPP) in the telecommunications industry is an open, industry standard protocol designed to provide a flexible data communication interface for the transfer of short message data between External Short Messaging Entities (ESMEs), Routing Entities (REs) and Message Centres.

SMPP is often used to allow third parties (e.g. value-added service providers like news organizations) to submit messages, often in bulk, but it may be used for SMS peering as well. SMPP is able to carry short messages including EMS, voicemail notifications, Cell Broadcasts, messages including messages (used to deliver MMS notifications), USSD messages and others. Because of its versatility and support for non-GSM SMS protocols, like UMTS, IS-95 (CDMA), CDMA2000, ANSI-136 (TDMA) and iDEN, the SMPP is the most commonly used protocol for short message exchange outside SS7 networks.

Contrary to its name, the SMPP uses the client-server model of operation. The Short Message Service Center (SMSC) usually acts as a server, awaiting connections from ESMEs. When SMPP is used for SMS peering, the sending MC usually acts as a client.

The protocol is based on pairs of request/response PDUs (, or packets) exchanged over OSI layer 4 ( session or X.25 SVC3) connections. The well-known port assigned by the IANA for SMPP when operating over is 2775, but multiple arbitrary port numbers are often used in messaging environments.

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