The Short Message Peer-to-Peer (SMPP) protocol is a
telecommunications industry protocol for exchanging SMS messages
between SMS peer entities such as short message service centres. It
is often used to allow third parties (e.g. value-added service
providers like news organisations) to submit messages, often in
bulk.
SMPP was originally designed by Aldiscon, a small Irish company
that was later acquired by Logica (now split off and known as
Acision). In 1999, Logica formally handed over SMPP to the SMPP
Developers Forum, later renamed as The SMS Forum and now disbanded.
The SMPP protocol specifications are still available through the
website which also carries a notice stating that it will be taken
down at the end of 2007. As part of the original handover terms,
SMPP ownership has now returned to Acision due to the disbanding of
the SMS forum.
The protocol is based on pairs of request/response PDUs
(protocol data units, or packets) exchanged over OSI layer 4 (TCP
session or X.25 SVC3) connections. PDUs are binary encoded for
efficiency.
The most commonly used versions of SMPP are v3.3, the most
widely supported standard, and v3.4, which adds transceiver support
(single connections that can send and receive messages). Data
exchange may be synchronous, where each peer must wait for a
response for each PDU being sent, and asynchronous, where multiple
requests can be issued in one go and acknowledged in a skew order
by the other peer. The latest version of SMPP is v5.0.
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