A Basic VoIP Architecture

Basic VoIP Architecture

When looking at any VoIP network, the basic VoIP architecture is made up of a number of components, and a number of inter-linking networks, all built around the core frame of the Internet.

In this section, we will have a look at some of the key components of the basic VoIP architecture, and introduce network diagrams that help explain how it all fits together. Without looking at a detailed VoIP softswitch architecture, it's easy to see how the different components of the network fit together.

At a top Service Provider level, the key components of a VoIP network are the different Carrier networks that peer with one another and hence allow the exchange of traffic between them. This is how VoIP traffic can be sent directly from one location to another without the need for dedicated (and often expensive) circuits between those two points.

The VoIP network diagram below shows the core framework of a basic VoIP architecture :

If we start at the top, we have an Application Service Provider who may have VoIP traffic that needs to be delivered via the Internet to a final location around the other side of the world, say on the SIP Network.

These packets are sent out to the Internet via a Session Border Controller (SBC). IP routers manage the packets to ensure they are sent efficiently to the destination network.

The SIP network itself is connected to the public Internet, and receives the VoIP traffic that had originated on the ASP's network.

On receipt of this traffic, the SIP network end-user receives the packet information, which is converted back into a voice stream.

Similarly, if the VoIP traffic had originated on the PSTN network within this basic VoIP architecture, this network will be connected to the public Internet via Media Gateways, which will convert the media stream into a format that can be sent via an IP network. In reverse, the Media Gateway can manage the flow of traffic into the PSTN from an IP network.

In the case of the Enterprise customers, all connected to the Internet via a broadband network, packet data will pass from this broadband network onto the Internet, where it will be routed to its final destination.

So this is the basic VoIP architecture that allows calls to pass from one point to another via the Internet.

The VoIP network diagram below takes a look at how the peering of Service Providers creates the framework of a basic VoIP architecture :



As you can see, the global basic VoIP architecture is made up of a network of both TDM and VoIP Service Providers, many of whom are interconnected to eachother. Therefore, even though two networks may not be directly interconnected, this global Internet infrastructure allows packet data to travel between two endpoints and hence reach its destination.

The end-users may be connected to a mobile network, a PSTN network or a VoIP network, but given the appropriate equipment within the network, there are no boundaries between them.

Now you have an idea of how the pieces fit together, it's time to start looking at the benefits and drawbacks that VoIP brings to a Voice Carrier.