What is an SMS Bulk service? What are the different forms of bulk messaging and how do they work?
Bulk SMS is a service that allows a business to quickly send a large number of SMS messages to a targeted audience. This is achieved by using an application that sends the text to the recipients’ mobile phones.
The service user may send identical or distinct SMS to the specified recipients. For that, an SMS sender loads the target phone numbers into a web portal or a software application.
After defining a target list, he can schedule various campaigns.
How does an SMS work in the GSM network?
A sender must have an active SIM card on a mobile device to send a usual SMS. The process involves typing a text, choosing a recipient, and pressing the send button. While in the case of Bulk SMS, the sender is an application. If the target number is active, the network delivers the text. Otherwise, the application gets an error response.
What is a text message as per the GSM standards?
An SMS is a message that has been encoded in accordance with the GSM standards. Both the sender and the recipient need to follow the same format and procedures mentioned in the protocol specifications for the service. The standard protocol enables an SMS text to be displayed in a human-readable format on any handset. GSM map is the message format protocol that encapsulates text and other details in a standard format.
What types of messaging flows are there?
Application-to-Person (A2P) messaging is a type of messaging in which a software or web application sends SMS messages to mobile devices. The sender application uses the APIs of the bulk SMS service provider. Sending an SMS from the web portal is an example of A2P messaging.
Companies such as banks integrate APIs into the software application for sending a text from the back-end software to the service user. OTP message is one of the examples where an online money transfer transaction authorizes a bank customer.
Person-to-Person (P2P) messaging is the primary and essential messaging service that a mobile operator provides to its subscribers, along with Voice. In p2p messaging, a mobile subscriber sends a text or SMS to another mobile subscriber. Sending an SMS from your phone to a friend’s phone is an example of P2P messaging. The sender and receiver may belong to the same or different mobile network operators.
The mobile operator bills the service user for SMS. The cost is based on the location of the sender and receiver. For example, if a subscriber wants to send an international SMS, the prices are higher than for a text to a local phone number.
Person to Application (P2A) is a scenario where a mobile user sends a text to a software application. Using a short code (e.g., 515151) to send an SMS for voting or any other service (such as checking your bank account balance) is an example of P2A.
What is Short Messaging Service in Bulk?
Sending and receiving a text is an essential function in the GSM network. It is under the control of a mobile operator. The facility gets active with the provisioning of a SIM card on the HLR.
SS7 is the transport network that encloses text inside the protocol messages in an encoded byte stream. The maximum allowed length is 160 bytes. Suppose a message is too long and exceeds the maximum length. It is segmented at the source and afterward assembled at the destination.
What is Bulk Messaging Service?
Some companies provide platforms for sending and receiving texts using the web or a software application. The platform offers a Bulk messaging service. A service user can connect to the platform over the internet.
The platform exposes the APIs to use the service APIs that an SMS user can integrate with an SMS software application. Enables a user to send bulk text without deploying an SMS gateway software and connecting to a complex telecom network.
What are the advantages of a bulk SMS service?
- Being an essential service, SMS works on all types of devices. In many countries, most of the population lives in rural areas and doesn’t have smartphones. Enables the advertisement on mobile phones without an active internet connection.
- People read SMS more often than reading emails. SMS alerts the user, and then the user usually checks SMS.
- SMS can be targeted based on the current location, while other services do not have a real-time subscriber location.
- An alphanumeric sender ID provides better brand awareness. Sending an SMS from the mobile device displays the sender’s mobile number. With an SMS API, a service user can set a sender ID based on the brand they want to promote.
- Extensive coverage with messaging. These days, almost everyone carries a mobile phone. To advertise any business, mobile phones are the biggest platform to reach the target audience.
- SMS gateway hides the complex structure of the telecom network. Enables a service user to develop a bulk SMS application quickly.
- Almost every business model has a use case for bulk SMS service. Banks, stores, schools, etc., require Bulk SMS.
How to use a software application and gateway for Bulk SMS?
There are different options if a company or person wants to develop software for Bulk SMS.
Connecting Directly To Mobile Operators over SS7/Sigtran:
The SS7 or SIGTRAN protocol provides an option for a direct connection with the Mobile Network Operator’s network. An SMS gateway or a Bulk SMS sender application connects to all operators over the SS7 or Sigtran (SS7 over IP) links. For service users, the app provides SMPP- or HTTP-based Bulk SMS APIs. This way, the SMS gateway hides all protocol-level difficulties from a common user. A direct connection to SS7 or Sigtran enables a bulk SMS service provider to deliver SMS messages quickly and accurately. It’s also a cheaper option, as it offloads the mobile operator’s SMSC.
Connect to the SMSCs of mobile operators over SMPP.
The bulk SMS service application connects network operator SMSCs over the SMPP Protocol with this option for sending and receiving a text.
Using Aggregators over SMPP or HTTP-based APIs:
With this option, an SMS gateway service provider connects to other aggregators for sending SMS to mobile phones.
What are a long code and a short code used for in messaging?
Shortcode is a 5 or 6 digits number (e.g., 344512), which is easy to remember. A mobile device can send an SMS to a shortcode.
Telecom networks route the shortcode toward the serving gateway for that shortcode. Gateway routes messages to the serving bulk SMS receiver application or content provider.
A content provider can rent out a Short Code from an SMS service provider.
Using a shortcode, a business can get queries from mobile subscribers. Later, a web portal can show all received questions.
The SMS received has a sending party contact number. No need to buy a database for target customers and get a pool of interested customers for the company. A long code is a ten-digit number.
What is a shared Long or Short Code for Bulk messaging?
A number can be shared between many content providers. Providers can be differentiated based on the KEYWORD. This option is cheaper than having a full dedicated short or long code for a service user.
MT-SMS Call flow by a bulk SMS service user:
Mt SMS call flow, or A2P SMS call flow, is for messages sent by a user or content provider from a software to a mobile device. The application submits SMS (text, mobile number, source number) over SMPP or HTTP to the Bulk SMS gateway.
The Bulk SMS gateway performs an HLR lookup over SS7/Sigtran to obtain the subscriber’s IMSI and MSC numbers. An HLR lookup over SS7, SRI-SM GSM MAP level message is sent over SS7 to the HLR of the subscriber.
If an error response is present in the delivery report from the HLR lookup, the gateway sends an error to the SMS application software. If the error is for temporary problems (e.g., subscriber not reachable), the application may retry after some time.
If the error is permanent (e.g., unknown subscriber), the application may remove the phone number from the list for a more accurate database.
Suppose IMSI and MSC numbers are present in the HLR lookup response. The gateway sends MT Forward SM to the MSC with IMSI, and the delivery report is returned to the application upon receiving the MT Forward SM response.
MO-SMS Call flow for short or long code:
- P2A is a type of MO-SMS.
- The mobile subscriber sends an SMS to a long or short code. In turn, the roaming MSC sends an MO SMS to the SMSC of the serving mobile operator.
- SMSC address is derived from the SMSC number stored in the phone.
- The SMSC sends a text to the gateway serving the short/long code over SS7.
- The gateway sends the application, which serves the short/long code.
What are the services provided by a bulk SMS provider?
Email to SMS service:
This service allows sending email messages to mobile devices via SMS. A mobile subscriber may subscribe to this service from an SMS gateway provider. Using this facility allows a person to view email text even without internet connectivity.
Excel to SMS:
A service provider can get SMS input in Excel in a fixed format. Excel has thousands of SMS for SMS campaign marketing. To send bulk SMS, a service user uploads the Excel file to the service provider portal for sending SMS to all numbers mentioned in the Excel file. After sending an SMS, a service provider provides a delivery report.
What is the SDK for integrating the Bulk messaging service?
SDK is a software development kit. It is a library containing prebuilt functions that support user and gateway interactions. Bulk SMS providers expose the API to the service user. The SMS service may require complex message encoding and decoding. To hide the complexity, SMS service providers provide SDKs. The user can quickly develop SMS applications by including the SDK in an application. The SDK might be in Java, PHP, etc. For example, it is difficult to parse the response to a message from the hex stream. SDK may provide a callback function for a response where a user can get a response code, text, etc.
How to select suitable APIs for a messaging service?
A bulk SMS provider offers APIs for sending content via SMS. APIs are accessible via the internet through the service providers’ SMS gateways. One can choose any provider worldwide. The following factors help in choosing a bulk SMS provider.
SMS Coverage:
A significant factor is that if a provider doesn’t have coverage in an area where SMS needs to be sent, there is no use for APIs. SMS Coverage might be for a country or a city.
HLR Lookup:
Bulk SMS senders use the HLR lookup service to clean invalid numbers. It gets mobile number portability and real-time location information for a mobile user before sending an SMS.
This saves cost and can target SMS based on the current location and the serving mobile operator. If a mobile user of country A is roaming in country B and an SMS is targeted to country A offers, then there is no use in sending an SMS to the user. From mobile number portability, an SMS can be targeted to the subscribers of a particular mobile operator. This is possible based on the information obtained from the HLR lookup.
SMS Delivery Reports:
The accuracy and latency are essential for sending SMS. Before buying, get a test account and check the delivery reports and latency.
SMS Cost :
Choose the package that is most suitable for you. An SMS provider offers a longer validity period for a bulk SMS package. This will help you to decide the quality of the service.
How does a Bulk SMS reseller work?
A Bulk SMS provider purchases SMS in bulk from mobile operators. It can now act as an SMS gateway for other Bulk SMS providers. To start a business, a vendor can connect to another Bulk SMS provider and provide SMS service to the end-users. This provider is called a reseller. This chain may grow further. The reseller always depends on the original seller. If the seller lost coverage in an area, the reseller would also lose coverage. The seller maintains multiple accounts for many resellers. Each has its own dashboard to check the statistics of the report. A reseller may get connections from various sellers. Based on coverage and cost, the seller gateway decided to send SMS.