For Promotional Bulk SMS

Promotional sms are being used for the promotions or marketing your services or products such Promotional SMS contains sales & marketing sms activity.

For Transactional Bulk SMS 
Transactional SMS have come for this purpose.They assist in sending the right amount of information to the right set of public at the right time

The biggest advantage of Transactional Bulk SMS is that  they can be sent  24 x 7 with your sender ID