An ESME bound as a Transceiver is allowed to send messages to the SMSC and receive
messages from the SMSC over a single SMPP session.
The purpose of the SMPP bind operation is to register an instance of an ESME with the SMSC
system and request an SMPP session over this network connection for the submission or
delivery of messages. Thus, the Bind operation may be viewed as a form of SMSC login request
to authenticate the ESME entity wishing to establish a connection.
As described previously, an ESME may bind to the SMSC as either a Transmitter (called ESME
Transmitter), a Receiver (called ESME Receiver) or a Transceiver (called ESME Transceiver).
There are three SMPP bind PDUs to support the various modes of operation, namely
bind_transmitter, bind_transceiver and bind_receiver. The command_id field setting specifies
which PDU is being used.
An ESME may bind as both an SMPP Transmitter and Receiver using separate
bind_transmitter and bind_receiver operations (having first established two separate network
connections). Alternatively an ESME can also bind as a Transceiver having first established a
single network connection.
If an SMSC does not support the bind_transmitter and bind_receiver operations then it should
return a response message with an "Invalid Command ID" error and the ESME should
reattempt to bind using the bind_transceiver operation. Similarly if an SMSC does not support
the bind_transceiver command then it should return a response message with an "Invalid
Command ID" error and the ESME should reattempt to bind using the bind_transmitter or