India SMS Features and Restrictions
Important update & action required for Domestic DLT registered Customers
On 16th February 2023, the Telecom Regulatory Authority of India (TRAI) issued a Regulatory Direction regarding measures to ‘Curb misuse of Headers and Content Templates’ under Telecom Commercial Communication Customer Preference Regulation, 2018.
Under this Regulatory Direction, if you have registered on the India DLT Platform(s), you will need to take the following actions on or before the below listed deadlines:
- Re-Verify all your Headers (Sender ID) on the DLT platform that you have registered with. Release/surrender the headers that are not in use. Headers that are not validated on or before 31st March 2023 will be deactivated.
- Re-Validate all your Content Templates registered on the DLT platform and make sure it complies with the 'variable' format on or before 15th April 2023:
- All content templates (New or Old) will be limited to have up to 2 non-consecutive variables only. In case of any exigency, a 3rd variable might be allowed with specific reasons provided to the DLT platform provider during the registration. The variable length should not exceed 30 characters, including the spaces.
- Templates that are not validated or do not adhere to the 'variable' format by the deadline will be deactivated.
The India DLT platform providers should have sent out the related notification to their registered customers. If you haven’t received the notification yet from your respective DLT platform(s), please reach out to them directly.
Since Vonage has no visibility on what you have registered on the DLT platform(s), unfortunately we can't help you in the above Re-Verify and Re-Validate process. We request you to kindly go through these Directions thoroughly and perform the required actions ASAP to avoid any traffic disruption towards India.
Vonage supports Domestic and International enterprise SMS business to India.
To follow the regulations of the Telecom Regulatory Authority of India (TRAI), domestic enterprises can only submit A2P SMS through domestic connections to end recipients after successful registration with Distributed Ledger Technology (DLT).
DLT aims to create a cleaner and transparent system in the Indian telecom industry and curb Unsolicited Commercial Communication (UCC) and an enhanced mobile subscriber policy. Information on the regulation can be reviewed here.
Any enterprise that fails to pre-register Distributed Ledger Technology (DLT) will become non-compliant and will not be able to send A2P SMS to end recipients via domestic connections.
International Enterprises are not affected by this DLT regulations. International customers can contact support or their account managers to enable ILDO routing for them if they intend to send pure OTP/Trans or Opt-in promo sms.
DLT Implementation History
Phase 1 - Sender ID/Header Scrubbing. Live since 1st June 2020.
Phase 2 - PEID/Entity Unique ID Scrubbing. Live since 19 November 2020.
Phase 3 - Template/Content Scrubbing. Live since 1 April 2021.
Phase 4 - Consent Upload in DLT. Live since 15th July 2021.
DLT Requirements (For Domestic Customers only)
- It is mandatory to have a brand name in all categories of messages.
- The exact text should match from your application to suppliers to the DLT Platform.
- Only Approved Templates should be submitted to Vonage.
- Header Mapping against each template should be verified.
- Where header ‘X’ is mapped on the DLT platform with a ‘Y’ text, then it should be used accordingly.
- If you wish to use any other header, changes on the DLT platform should be done accordingly.
- The variable length should not exceed 30 characters.
- 30 characters per variable including the spaces and the content templates can be registered with variables in GSM (English) characters and in unicode (for local dialect characters).
- If it is more than 30, you will need to add more variables but maximum 2 non-consecutive variables are allowed in total.
Registering for DLT (Domestic Customers Only)
To send any SMS through domestic connections, all enterprises must register their Principal Entity, Headers, Templates with the Brand Name, and provide consent on one of the approved DLT systems:
- Vodafone-Idea Ltd DLT Portal
- BSNL DLT Portal
- Airtel DLT Portal
- Reliance JIO DLT Portal
- Videocon DLT Portal
Maintaining Compliance While Submitting Messages to the Vonage Platform
After you have registered for DLT with one of the portals, there are two ways to ensure your traffic is compliant with DLT.
Vonage is not responsible for domestic entities registering for DLT. We do not verify if domestic entities have correctly provided their PEID, Sender ID, and Template IDs.
If a message errors due to these fields not being provided or valid, the carrier does this will be reflected in the Delivery Receipt webhook and SMPP DLR.
You can read a tutorial by our Developer Relations team discussing DLT and how to implement it.
Option 1: Submit Required DLT Parameters with Every Request
- Make the necessary changes on your end so that your Entity ID, Sender ID, Header, and Templates (as registered with DLT) are sent with every API submission (see additional properties you must use below).
- Inform Vonage in a support request to enable routing for Option 1 for your Sender ID.
- Start sending SMS after you have received confirmation routing has been enabled for you.
Option 2: Let Vonage Detect Your Template (This option is no longer supported after Feb-2023)
- Create your DLT Details .csv file.
- Download the template file from your DLT Portal.
- Add your details to this file.
- Save as <entityid>.csv where <entityid> is your Entity ID.
- Register for DLT with Vonage by submitting a support request with the following information:
- Your PEID - Entity unique ID received from DLT after entity registration approved.
- Entity Name - Company name registered on DLT.
- Sender Name - Six character alphanumeric Sender/Header, which has been registered and approved in DLT.
- The name of which DLT system you are registered on.
- Your DLT details file (mentioned above).
Additional Parameters or Properties to Support DLT
Vonage has added functionality within our Send SMS API endpoint or via SMPP to allow domestic entities to comply with the DLT regulation by providing both their PEID (unique entity ID) and the template ID for every SMS request made. (for Option 1 customers as stated above)
The API properties used in this endpoint are to be matched exactly as listed below:
- ‘entity-id’ parameter needs to be the DLT approved PEID (unique Entity ID)
- ‘content-id’ parameter needs to be the DLT approved Template ID
- ‘from’ parameter needs to be the DLT approved Sender ID (Header ID)
- If you use SMPP to send SMS messages with Vonage, the following fields apply:
- 0x1470 needs to be the DLT approved PEID (unique Entity ID)
- 0x1471 needs to be the DLT approved Template ID
- The Sender ID needs to be the DLT approved Sender ID (Header ID)
Vonage Error Codes for DLT Related Issues
|50||DLT entity ID details are missing or wrong (includes null + invalid value)|
|51||DLT header ID (Sender ID) details are missing or wrong (the Sender IDs must be registered with suppliers but not with DLT platform)|
|52||DLT content ID details are missing or wrong|
|53||DLT error for consent|
|54||DLT generic error|
By default, users will fall into the International promotional (SMS without opt-in) category with restrictions as mentioned below.
If you are an International user or have a different SMS type than is listed below, contact your account manager or submit a support request.
|Traffic Type||Content Allowed||Sender ID||Restrictions/Regulation|
|Domestic Transactional||Transactional traffic, OTP||6 digit alpha with DLT pre-registration.||No restrictions. 24/7 delivery without NDNC restrictions.
Registered Alpha Sender ID will be added with 2 letters as a prefix, depending on which carrier was used to deliver the SMS to the final operator or 2 random numbers; e.g., MD-XXXXXX (where XXXXXX is the registered Sender ID).
|Promo/Marketing Content||6 digit numeric with DLT pre-registration.||
Promo SMS will be blocked to numbers registered in NDNC as per TRAI regulation.
DLR not supported since 9 Oct 2020.
|International (transactional/opted-in promo)||
International originated transactional content & Opt-in Promo content.
(If the client registered in India, but the SMS message originated from outside India, it will be identified as International traffic).
|Sender ID not supported and will be changed to a random short/long virtual number.||
For OTP/Transactional traffic mainly. For Opted-in promo, content needs whitelisting through Support or your Account Manager before sending SMS.
SMS Delivered 24/7 via International route.
|International Promotional (without opt-in) Default route||Promo/Marketing Content||Sender ID not supported and will be changed to a random short/long virtual number.||
Delivery on best effort basis with shared SC from SMS partner.
10am-9pm(IST) delivery to non-NDNC customers only.
Domestic Customer: Alpha SenderID supported. Refer to DLT registration as mentioned above for SID registration. For enterprises that finished the DLT application successfully, the SMS Sender ID will be prefixed with an additional two letters, depending on which final operator the number belongs to. A full list of prefixes can be found here: India Pre-registered Sender ID Prefixes.
International Customer: Alpha Sender ID is not supported for International customers and will be changed to a random short code. Please contact Support or your account manager for ILDO route if your sms is purely transactional or Opt-in promo type.
Do Not Call Registry/Do Not Disturb Service
Promotional SMS are barred and will get blocked by operators to numbers those registered in the Indian NDNC (National Do Not Call registry).
SMS delivery is blocked between 21:00 – 10:00 hours IST for end recipients who registered with Do Not Disturb Service (DND). This means promotional SMS can only be delivered only between 10:00 - 21:00 hours IST.
Operators do not support delivery notifications for messages sent via promotional routes with numeric headers.
Any Vonage customer expecting to send promotional content to their end-users under the Service Explicit category with legitimate PE ID and content template registrations are being advised to have their end user customer consents re uploaded to their DLT portal via the consent upload menu ASAP to avoid any delivery interruptions.
Of late, Operators have been receiving many UCC complaints from DND-registered subscribers for receipt of promotional messages from Service headers.
In view of these unceasing complaints, effective on 8th February 2022, Operator will be making changes in the scrubbing logic for all service explicit messages to block them based on DND preferences. Since consents override DND preferences, we encourage you to upload consents via consents upload menu that is available on Operator DLT portal.
Limitation to Avoid Potential SMS Flooding
Local regulations specify limitations to the number of messages that can be sent to the same number:
- More than six messages to the same destination number within an hour with the same sender or text may be blocked.
- Users may not receive more than a total of 200 SMS per day across all incoming streams.
Unicode is supported for All India Networks.
Concatenated SMS is supported for All India Networks.
- Transactional/OTP Traffic: DLR is supported and its reliable delivery receipts.
- Promotional Traffic: DLR is not supported, or its unreliable Network DLR.
Traffic Restriction by Political Reason
Messages towards Jammu and Kashmir networks (for example, 405/55 - Airtel J&K) will be blocked by the government due to political sensitivity.
Political SMS is prohibited throughout the country during an election period.
For more information, see the following articles:
Notice: Edited and updated on 20/8/2014
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