Smpp protocol Parsing

The smpp protocol is an open industrial standard protocol. It provides flexible data communication interfaces for Information Centers and short message system application terminals during text message data transmission. The information center has short message center smsc gsm Unstructured Supplementary Service data. server ussd and other types of short message system applications include the WAP Proxy Server email gateway and some other information gateways.

Smpp supports the following two-way information transfer functions:

1. Send messages from external Esme to a single/multiple destination addresses through SMSC
2. Through SMSC, Esme can receive messages from other SME (such as mobile stations;
3. query the status of short messages stored in SMSC;
4. delete or replace a short message stored in SMSC;
5. Send a registration short message;
6. List the time and date of short message sending;
7. Select the message mode, such as datagram, storage, and forwarding;
8. Set the priority of short message sending
9. define short message data Code Type;
10. Set the short message Validity Period
11. Set service types for each short message, such as voice prompts.

Smpp Session Description
The smpp session between SMSC and Esme is initiated by Esme first, establishes a network connection with SMSC, then sends the smpp connection request to start the smpp session. ESME for message submission and receipt requires two network connections (TCP/IP or X.25) and two smpp session layers (forwarding end and receiving end ). In the Protocol Specification, Esme can also establish an smpp receiving and receiving Session Layer on a single network connection.
In smpp sessions, Esme can initiate a series of requests to SMSC to receive responses from SMSC. And vice versa.

The smpp protocol is an application layer protocol and does not provide the transmission function. Therefore, the underlying Network Connection provides point-to-point reliable data transmission. These transfers include encrypted packets, windows, traffic control, and error handling. Displays the running status between Esme and SMSC.

Message from Esme to SMSC

1. submit_sm -- submit short message data to SMSC

2. data_sm -- transmit data to SMSC

3. query_sm -- query the status of the previously submitted message from SMSC

4. cancel_sm -- cancel the short message sent previously submitted

5. replace_sm -- replace the previously submitted short message

SMSCToEsmeResponse Message

1. submit_sm_resp

2. data_sm_resp

3. query_sm_resp

4. cancel_sm_resp

5. replace_sm_resp

Message Mode

1. Storage and forwarding mode. Generally, short messages are stored in the SMSC database before being sent. In this way, the short message can be securely saved until the SMSC attempts to forward the message successfully. This message mode is called "Storage and forwarding"

2. the datagram message mode draws on the experience of other communication protocols, such as UDP datagram package transmission, to focus on sending large amounts of information. His disadvantage is that there is no secure storage, and there is no attempt to guarantee forwarding in the storage and forwarding modes. In the datagram message mode, the message initiator does not receive any form of sending status response.

3. The transaction processing message mode allows the Esme message initiator to receive and send a response in the smpp response PDU (to show whether the short message is successfully sent to the Mobile Terminal)

Message Type

In addition to normal short messages, submit_sm, deliver_sm, or data_sm commands can also transmit some special messages between Esme and SMSC. These message types are defined in the esm_class parameter in the above smpp command.

the following message types are supported in smpp.
SMSC delivery receept: After SMSC detects the final status of a registered message, it sends a message to the Message initiator.
intermediate notification: An intermediate message is a special message form that SMSC can send to ESME for mobile terminal message senders. It provides an intermediate status report for a message sending attempt.
SME delivery Acknowledgement: an SME response message is not a prompt sent by a short message to SME, but an instruction sent by the user who has read the short message.
SME manual/user Acknowledgement: The reply information for the request message.
conversation ABORT: not supported in all network types.

Esme connection mode

Esme forwarding end (bind_transmitter): As the forwarding end, Esme can send short messages to SMSC to receive SMSC response messages. In this case, Esme cannot receive the original messages sent by other SME (such as mobile base stations.
Esme receiving end (bind_receiver): As the receiving end, Esme can receive short messages sent by SMSC and return corresponding response messages.
Esme transceiver (bind_transceiver): As the receiver, Esme can send short messages and receive short messages to SMSC through an smpp conversation.