Definition
An SMPP bind is the login operation that opens an SMPP session. The client authenticates with a system_id and password and chooses to bind as transmitter (send), receiver (receive) or transceiver (both).
SMPP v3.4 defines three bind PDUs: bind_receiver (command_id 0x00000001), bind_transmitter (0x00000002) and bind_transceiver (0x00000009). The SMSC answers with the matching _resp PDU and a command_status, where 0 means success.
A transmitter bind can send submit_sm; a receiver bind receives deliver_sm (inbound messages and delivery receipts). A transceiver does both over one connection, which is the usual choice today.
The bind also carries system_type, interface_version (0x34 for v3.4) and address-range fields. Providers usually limit how many simultaneous binds an account may open and the throughput per bind.
Typical bind failures are a wrong password (ESME_RINVPASWD), a wrong system_id, an IP address that is not allow-listed, or exceeding the permitted number of binds. After binding, send enquire_link regularly so idle connections are not dropped.
Example
bind_transceiver: system_id="acme01", password="********", system_type="", interface_version=0x34