Technical Information on VMNs

Information on how VMNs operate

Mobile phone numbers belong to mobile networks and each mobile network's mobile numbers are set-up in what is known as the Home Location Register (HLR). The HLR is effectively a database that maintains the status of every mobile number and its mobile subscription. Virtual Mobile Numbers (VMNs) are also held in the HLR as they are also mobile numbers, however they aren't associated with a mobile subscription but instead with equipment on the operator's network that allows applications to receive the SMS text messages sent to those VMNs.


MO SMS in mobile-to-mobile scenario

Diagram: MO SMS from mobile user being delivered to destination mobile user as MT SMS


The delivery of the SMS text message is therefore slightly different when sending an SMS text message to a VMN compared with a regular mobile number. When sending to a regular mobile number the SMS goes from the sender's mobile to their network's Short Message Service Center (SMSC), that SMSC then finds out from the HLR where the mobile user is located and finally the SMSC sends the SMS to the Mobile Switching Center (MSC) of the destination mobile user's phone. In the case of VMNs, there is no destination mobile user's phone and instead the HLR is returning the location of the equipment that is there to receive the SMS being sent to VMNs. Once this equipment receives the SMS for a VMN it then passes it onto an application that's connected with this equipment using SMPP, HTTP or some other API.


MO SMS to application using Virtual Mobile Number (VMN)

Diagram: MO SMS to application using Virtual Mobile Number (VMN)


HLRs, SMSCs and VMN servers are located on a mobile network operator's SS7 network.


Features of VMN servers

  • Filter incoming SMS based on origin SMSC, origin mobile number / source address or content of message
  • Multiple APIs on the application side (SMPP, HTTP, REST, SOAP, MQ, SQL)
  • Rate limiting to control rate at which SMS can be received
  • Black/white/gray-listing of sending SMSCs
  • Multiple character sets support (UCS2, Latin-1/ISO-8859-*, GSM)
  • Application can receive the SMSC timestamp (SCTS) indicating when the SMS was sent by the mobile user
  • Optionally contain a HLR that is dedicated to the VMN MSISDN ranges instead of using MNO's regular mobile subscriber HLRs

Key technical points

Throughput

VMNs can receive SMS at a significantly greater rate than a regular mobile number. The SMS message doesn't need to traverse the destination radio network and therefore directly reaches the application. This allows a significant reduction in the time for the sending SMSC to receive an acknowledgement for the SMS it's sent and the receiving of SMS from different mobile users simultaneously, resulting in a greater capacity for receiving SMS.

Fast Delivery - Low Latency

Sending an SMS message to a VMN can result in the message reaching the application in less than 1 second from the time the user presses "send" on the mobile phone. This is due to there only being one mobile phone involved in the communication rather than a mobile on both the sending and receiving side. VMNs are associated with special equipment (e.g. "VMN servers") within the core of a mobile operator's network. There is no radio communication involved on the receiving side.

APIs

APIs such as Short Message Peer-to-Peer (SMPP) and HTTP can be used by an application to receive SMS text messages sent to VMNs. When using SMPP, an application would maintain an SMPP v3.3, SMPP v3.4 or SMPP v5 session with the VMN provider's systems and deliver_sm PDUs containing the received SMS would be sent to the application over this session as each SMS is received by the VMN. If instead using HTTP, a HTTPS request would be made to a callback URL or webhook as each SMS is received and the content of that SMS would be passed to the application in the HTTPS request.


VirtualMobile - Broker

VirtualMobile makes is easy to obtain Virtual Mobile Numbers from mobile networks around the work. Use VMNs to enable your application to receive SMS and improve your customer engagement through their use.

Broker

We are a zero-commission and zero-fee broker who will match your request with a suitable supplier of VMNs.

Responsive

You will normally receive a response from a supplier within 8 working hours.

Service

You will use the service of the supplier from which the VMN is obtained to receive SMS sent to the VMN. Multiple APIs such as SMPP and HTTPS are normally available.