In the interest of the Access Service Providers and International Long Distance Operators the Internet telephony was permitted to the ISP with restrictions. Internet Telephony is considered to be different service in its scope, nature and kind from real time voice as offered by other Access Service Providers and Long Distance Carriers. Hence the following type of Internet Telephony are permitted in India:
Not every internet connection is VoIP ready, so before you sign up, make sure that your line will provide you with the level of VoIP speed and service you need. You can easily find resources online for checking the speed and call quality of your connection. The quality of your connection can potentially impact the clarity of your calls, so pay close attention.
In the case of a private VoIP system, the primary telephony system itself is located within the private infrastructure of the end user organisation. Usually, the system will be deployed on-premises at a site within the direct control of the organisation. This can provide numerous benefits in terms of QoS control (see below), cost scalability, and ensuring privacy and security of communications traffic. However, the responsibility for ensuring that the VoIP system remains performant and resilient is predominantly vested in the end user organisation. This is not the case with a Hosted VoIP solution.
E.164 is a global FGFnumbering standard for both the PSTN and PLMN. Most VoIP implementations support E.164 to allow calls to be routed to and from VoIP subscribers and the PSTN/PLMN. VoIP implementations can also allow other identification techniques to be used. For example, Skype allows subscribers to choose "Skype names" (usernames) whereas SIP implementations can use URIs similar to email addresses. Often VoIP implementations employ methods of translating non-E.164 identifiers to E.164 numbers and vice versa, such as the Skype-In service provided by Skype and the ENUM service in IMS and SIP.
Be aware, however, that there are significant security implications regarding the use of mobile softphones on employee-owned devices. While it's possible for your employees to simply download the appropriate software from their respective app store, your IT department should be involved with allowing access while also confirming that necessary security steps are taken. Also be aware that there are important reasons not to allow soft phone installations on private devices of any type because you may not be able to remove that phone client if the employee leaves the company, and because local laws may impact how much control you have over the use of the device.
From an end user point of view, the actual phone service works in the same way, you pick up the phone to answer a call or to dial a number just like with a landline service. Number porting means you can keep your existing phone number and simply switch it over to your new service provider. The residential VoIP providers take care of the call routing and you can call any destination and receive calls from anyone, just like with regular home phone service.