Posted: 05/2006

Parts Ain’t Parts

ONE OF THE BIGGEST CHALLENGES

in implementing a VoIP solution is making sure all the necessary components are there and working together this is not a case of parts is parts. Unfortunately for dealers, the nomenclature makes it difficult: solutions used in the network are billed as VoIP gateways, media gateways, IP switches and more. So, whats what?

Making things tougher is that call managers, convergence servers and a variety of other media modules sound like generic terms but are usually proprietary names fashioned by company marketing wizards. Its important to disregard the names and determine the function.

The basic anatomy of a VoIP solution comprises several main parts beyond the IP transport network itself:

Now, lets dive deeper into these categories.

IP Phones.

To get the architecture of these networks VoIP-ready means putting in IP desk sets, or phones, of which there are a variety on offer. Some work only with vendor-specific platforms; others are interoperable with gear from rivals.

Media/VoIP Gateways.

On the network side, a common element in a VoIP-enabled environment is a gateway that extends an existing TDM network to VoIP infrastructure. Often called a media gateway, a VoIP gateway or even an access gateway, these often plug into an existing PBX to convert either voice or signaling information from traditional TDM networks into a format suitable for transmission over IP networks. They can be configured to support toll-bypass calling across the WAN between branch locations. Many gateways also provide connectivity from an internal VoIP network to the PSTN, for those that need trunking to the outside world. Sometimes, this is a separate element known as a trunking gateway.

Hybrid PBXs.

Gateways are not to be confused with hybrid PBXs, which support traditional PBX and phone extensions, as well as VoIP phones connected via Ethernet. This enables an environment where there are multiple types of voice traffic being routed, yet four-digit dialing and the other call functions work across them.

P PBXs.

In a pure IP telephony-ready network, determining who wants to talk to whom by linking IP addresses with phone numbers is done by whats commonly called an IP PBX also known as a media server, a call server, an enterprise softswitch or simply an IP switch. Although it sounds like it is hardware, its actually a server and software platform.

Application and feature servers

are software platforms that provide management of IP-based rich media such as video, multimedia presentations, graphics, data services and so on that have been integrated into the converged environment.

Security gateways

and session border controllers take care of encoding, encryption, firewall traversal and other security concerns.