Configuring the SMPP Server

SMPP Server Options

When delivering long text messages that must be segmented over multiple SMS messages, or when delivering messages that include port numbers such as for WAP push, NowSMS encodes the message with the appropriate GSM User Data Header (UDH) fields. When the “Use TLV parameters for port numbers and segmentation” option is enabled, NowSMS will instead use optional TLV parameters in the SMPP header for port numbers and segmentation. Specifically port numbers will be encoded in the source_port and destination_port parameters, and segmentation will be encoded in the sar_msg_ref_num, sar_total_segments, and sar_segment_seqnum parameters. Regardless of the setting of this parameter, SMPP clients can either encode messages for submission to NowSMS using either GSM UDH or TLV parameters. This setting only controls which format NowSMS uses when delivering messages back to SMPP clients.

SMSC Character Set – By default, NowSMS uses the GSM character set when delivering SMS messages via SMPP, and it indicates via the data_coding parameter that the default encoding is used. If you experience a problem where @ symbols and other characters do not appear correctly in received messages, your SMSC client might be expecting a different character set. Assuming that you are working in a GSM environment primarily, first try changing this setting to “IA5 (GSM)”. When this setting is applied, NowSMS will still use the GSM character set, but it will set a flag in the header to indicate this. If the character problems persist, change this setting to “iso-8859-1 (Latin)”, which is the standard character set used in Western Europe.

Enquire Link Timeout – SMPP clients are expected to periodically send enquire_link commands when connected to an SMSC. These commands are used to tell the SMSC that the client is still alive and functioning properly. If NowSMS does not receive an enquire_link command, or some other activity, from a connected SMPP client within this timeout period, NowSMS will automatically disconnect and release the client connection. It is not recommended to set a value for this parameter less than 60 seconds. However, a special setting of 0 can be used to disable this timeout, allowing clients to remain connected without sending the enquire_link command.

Max Connections Per Client – This specifies the maximum number of simultaneous connections allowed from any one SMPP client account (although it is possible to override this value on a per account basis). Note that many SMPP clients create two separate connections, 1 for sending and 1 for receiving, so a value of 1 may cause problems.