The Short Message Peer to Peer (SMPP) protocol is an open, industry standard protocol designed to provide a flexible data communications interface for transfer of short message data between a Message Center, such as a Short Message Service Centre (SMSC), GSM Unstructured Supplementary Services Data (USSD) Server or other type of Message Center and a SMS application system, such as a WAP Proxy Server, EMail Gateway or other Messaging Gateway.

SMPP supports a full featured set of two-way messaging functions such as:-

• Transmit messages from an ESME to single or multiple destinations via the SMSC

• An ESME may receive messages via the SMSC from other SME’s (e.g. mobile stations).

• Query the status of a short message stored on the SMSC

• Cancel or replace a short message stored on the SMSC

• Send a registered short message (for which a ‘delivery receipt’ will be returned by the SMSC to the message originator)

• Schedule the message delivery date and time

• Select the message mode, i.e. datagram or store and forward

• Set the delivery priority of the short message

• Define the data coding type of the short message

• Set the short message validity period

• Associate a service type with each message e.g. voice mail notification