IP PBX: How an IP PBX / VoIP Phone System Works

Question

Let me put the context first -
Sometime back Airtel (fourth largest operator in the world with total 300m+ subscribers) has announced that VoIP calls (skype, sip etc) would be charged higher then normal data access to discourage the data usage for Voice.

Now all of us know net-neutrality is not the reality but was it fair, what would be the long term impact of this on call rate, telecom sector profitability etc.

(by the way they have roll backed the plan but legally they can roll out anytime as net neutrality is only for the wire-line infrastructure by law)

Want to know the opinion of the others?

Answer 1

A VoIP Phone System / IP PBX system consists of one or more SIP phones / VoIP phones, an IP PBX server and optionally includes a VoIP Gateway. The IP PBX server is similar to a proxy server: SIP clients, being either soft phones or hardware based phones, register with the IP PBX server, and when they wish to make a call they ask the IP PBX to establish the connection. The IP PBX has a directory of all phones/users and their corresponding SIP address and thus is able to connect an internal call or route an external call via either a VoIP gateway or a VoIP service provider to the desired destination.

An example of how an IP PBX / VoIP Phone System integrates on the network and how it uses the PSTN or Internet to connect calls is shown above.