Adding VoIP to your legacy networks

Speaker: Jennifer Stafford, voice engineer, CNET

Description: If you think switching to VoIP means ripping out your traditional phone network, think again. CNET's Jennifer Stafford shows how a few simple steps can make the transition less daunting.


Hi, I'm Jennifer Stafford and I'm a Voice Engineer here at CNET Networks. I'm here today to talk to you about adding voiceover IP to your legacy network. So most companies have spent a good deal of money on their existing PBX and voicemail infrastructure. Generally they don't want to just tear that out in the interest of trying something new. So we're going to show you how you can introduce VoIP a little at a time to your legacy network.

In the traditional model you have a PBX connected to a separate voicemail system and generally you would connect your remote office using the public switch telephone network or telephone companies. And this calling generally has a permanent cost associated with it.

So before I show you how to add VoIP to your legacy network, let's define a few terms. The call control is really the set-up and tear-down or beginning and end of each call and monitoring readiness of each line. The gatekeeper is really a table or list of numbers and information responsible for knowing where each line in the system and each extension lives relative to each other.

The gateway is really just a piece of equipment, a switch usually that's used to join your legacy equipment to the IP network. So let's put this into action. We'll start by installing a gateway at headquarters. We'll connect it with perhaps a T1 or perhaps even just a cable. We'll install another gateway here at the remote office. And between them, connect them with our IP network or WAN.

The great thing about this, fixed cost compared to the recurring charges. So no per-minute charges for your phone calls here. The functions of the call control and the gatekeeper, which are basically software, live here next to the gateway and enable us to connect IP phones connected on our LAN and over the VPN we can extend the same high quality phone service to the user at home. Same service as the user in the headquarters office and remote office.

So as you can see, with a little bit of equipment and software you're able to add voiceover IP to your legacy network without ripping out the guts of the system.