SMPP: the UDH (User Data Header) appears in the body of sms - php

Question

I would like to send long SMS with SMPP. I use this class php-smpp: https://github.com/agladkov/php-smpp/tree/master
and the doc http://opensmpp.org/specs/smppv34_gsmumts_ig_v10.pdf
However when I receive sms they are not concatenated.
Each sms Contains the following characters at the beginning: é¥ò#$$ (first sms) and é#¥$$$ (second sms)
These characters correspond to the UDH
esm_class = 0x40 ( for enable UDH )
public function sendSMS(SmppAddress $from, SmppAddress $to, $message, $tags=null, $dataCoding=SMPP::DATA_CODING_ISO8859_1, $priority=0x00, $scheduleDeliveryTime=null, $validityPeriod=null)
{
...
$seqnum = 1;
foreach ($parts as $part)
{
$udh = pack('cccccc',5,0,3,substr($csmsReference,1,1),count($parts),$seqnum);
$res = $this->submit_sm($from, $to, $udh.$part, $tags, $dataCoding, $priority, $scheduleDeliveryTime, $validityPeriod, (SmppClient::$sms_esm_class|0x40));
$seqnum++;
}
...
}
protected function submit_sm(SmppAddress $source, SmppAddress $destination, $short_message=null, $tags=null, $dataCoding=SMPP::DATA_CODING_DEFAULT, $priority=0x00, $scheduleDeliveryTime=null, $validityPeriod=null, $esmClass=null)
{
if (is_null($esmClass)) $esmClass = self::$sms_esm_class;
// Construct PDU with mandatory fields
$pdu = pack('a2cca'.(strlen($source->value)+1).'cca'.(strlen($destination->value)+1).'ccc'.($scheduleDeliveryTime ? 'a16x' : 'a1').($validityPeriod ? 'a16x' : 'a1').'ccccca'.(strlen($short_message)+(self::$sms_null_terminate_octetstrings ? 1 : 0)),
self::$sms_service_type,
$source->ton,
$source->npi,
$source->value,
$destination->ton,
$destination->npi,
$destination->value,
$esmClass,
self::$sms_protocol_id,
$priority,
$scheduleDeliveryTime,
$validityPeriod,
self::$sms_registered_delivery_flag,
self::$sms_replace_if_present_flag,
$dataCoding,
self::$sms_sm_default_msg_id,
strlen($short_message),//sm_length
$short_message//short_message
);
// Add any tags
if (!empty($tags)) {
foreach ($tags as $tag) {
$pdu .= $tag->getBinary();
}
}
$response=$this->sendCommand(SMPP::SUBMIT_SM,$pdu);
$body = unpack("a*msgid",$response->body);
return $body['msgid'];
}
Any help is appreciated.

Answer 1

When I added UDH fragmentaion support in "esme", I had same problem. But my problem was that UDHI was ignored (by my test server - i fixed that after that messages :)). If you receive wrong SMS on MS then you can try to implement SAR fragmentation, because it is used widely. SAR fragmentation is very similar, but you should set optional TLV parameters which start with sar_*