How a VoIP Call Is Set up
Dissecting a VoIP Call
For a long time there was no standardized way to perform a call over the Internet. And as everyone knows, without standards they can be no real growth of a given technology - especially one that relies so greatly on network effects like a communications application. When two people use two different protocols, they simply cannot talk to each other even though the underlying idea is the same. It wasn't until the formulation and wide acceptance of the SIP protocol that VoIP really took off and became a feasible alternative to the traditional PSTN network. Even now though, there are a great many VoIP applications that do not follow the SIP protocol and have their own locked in customer base. Skype is one example, and so are many of the other hundreds of VoIP applications you find on the market today.
Until and unless everyone uses a standardized way of talking to each other, they can be no network effects and no interconnectivity. So what exactly is this magical SIP protocol. And why has it become so popular? The reason is that SIP allows providers to implement a great many of their own elements without restricting them. It merely presides over the setting up and tearing down of VoIP calls – that is it restricts itself to the signaling aspect only. This provides a great deal of flexibility.
Setting up a VoIP Call
The SIP protocol deals with the initial communication and setting up between the two VoIP clients. Specifically, it deals with ascertaining over what ports the the real media is going to travel over. It's merely a setup for the RTP protocol that is most commonly used for conducting VoIP conversations. Normally this would be a fairly straightforward process with no complications. Unfortunately, the current structure of the Internet is such that many clients reside behind a NAT firewall. This NAT firewall hides the true IP addresses of each individual computer requiring a large number of workarounds to ascertain which ports will be used. This is because VoIP is a P2P protocol and direct communication between the two clients is necessary.
Despite the problems, there has been a significant amount of progress and many VoIP clients can now automatically detect the type of network and perform the necessary VoIP configurations Find a local Boston phone service provider to minimize the latency that you will encounter with Internet calling if you stay in the same area.
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