What is virtual phone number?
A virtual phone number is a VoIP number. It is similar to any other phone number, a mobile or fix line user have. But the main difference is that , this number does not belong to any sim card or to any fixed line device. Voip providers allocates the number along with voip account. Virtual number have many advantages. Main advantages are for business. For e.g a company having its customer care office in India , but the service is launched in any other countries. They have local number for each country. It is a very difficult task to setup customer care offices in each country. Here comes the main role of virtual number.
Services provider buys a virtual number for each country and the callers feels that they are talking to local guys. Virtual number provider routes all call to the India call center.
VoIP and Virtual Number:
The VoIP enables the virtual number concept. A non VoIp number have either the sim card or a fix line. The voip gateway provider terminates the request for the virtual number and connects to the actual number for voice and data. So it's like a getaway between IP and PSTN network. As all is on IP network this enables a cost-effective service to the service user.
The voice Call flow for Virtual Number :
Voice is the primary service which a telecom network provides. When a user dials the virtual number. Call reaches to the service provider. Provider Knows that this is called for the virtual phone number by looking at its database. If the phone number is not provisioned then call is dropped, else actual number is found and provider initiates a new call towards actual number and connects both the calls. On voip side the signalling protocol is SIP and on PSTN side the signalling protocol is ISUP. Sip if for setting a voice session over IP network and ISUP is the protocol for setting a Voice Channel over PSTN network or SS7 network. The called actual number can be a mobile number, a fix line number or a call centre number via SIP trunking.
SMS Flow for virtual number:
SMS or text is another basic service for any number. Similar to voice , the voip provider for virtual number forwards the sms to the actual number and sender gets the delivery report for the successful submission for the number.