Multinational VoIP Network Example

Above is an example of various ways that one customer can configure multiple locations with Voice over IP (VoIP) solutions.

In the SOHO/Branch Office section of the diagram, a customer can make outbound calls and receive inbound calls on an IP phone which sits behind a PIX firewall.  On outbound calls, the IP phone converts voice signals into data packets which are transported through the firewall and router and pushed over the public internet to the DOW Networks Gateways and Servers.  There the data packet is changed back to a voice signal and sent over the Public Switched Telephony Network (PSTN) and routed to its final destination.  In addition, you can set up a toll-free number to ring to the IP phone. 

With the legacy PBX configuration, the customer uses a Cisco IAD to connect to a traditional Time Division Multiplexing (TDM) protocol PBX.  On outbound calls, the call is passed from the traditional analog or digital phone to the PBX which then passes the voice signal to the Cisco Integrated Access Device (IAD).  There the voice signal is converted into a data packet and passes through the hub and router over the public internet to the DOW Networks Gateways and Servers.  Again, the data packet is changed back to a voice signal and sent over the Public Switched Telephony Network (PSTN) and routed to its final destination.  Just like the IP phone, you can set up toll-free numbers to ring to the customer premise.  

With the IP PBX configuration, the customer uses a combination of IP phones and an IP based PBX to push calls over the public internet.  The main difference between this and legacy PBX systems is that there is no need for an IAD because the IP phones take care of the conversions between voice signals and data packets.  In this variation, we have included an FXO router which the IP based PBX routes to for local calls. 

Calls between every phone in this network are free because they travel across the customer’s own Virtual Private Network (VPN) without ever touching the PSTN.  For example, say the SOHO office is in South Africa and the IP PBX config is in the United Kingdom; calls between these points would be free and would be as simple as dialing a 4 digit extension.