Access-edge gateways have merged the functionality of media gateways and session border controllers and added just about everything an enterprise needs to ensure secure and robust connectivity. Security mechanisms will typically include authentication, encryption, and validation for both signaling and media flows. And quality of service (QoS) will be assured by a combination of bandwidth and QoS-based call admission control; QoS mapping, monitoring and marking; and QoS based routing.

In addition they would be VoIP- and SIP-aware and support full-mesh or partial-mesh trunking topologies. This enables both least-cost and QoS-based routing, and by reducing or eliminating VoIP backhaul, direct routing between end points improves QoS and saves money.

The Eclipse product from Covergence (www.covergence. com), a company that is headquartered in Maynard, Mass., matches this connectivity paradigm. Eclipse and other access- edge gateways from other vendors can be located on a customer’s premises or in the network of the service provider. The latter allows operators to offer hosted services to customers who may lack the technical resources needed to handle today’s complex connectivity issues.

Service providers recognize that the key to capturing enterprise customers is to extend their service portfolios beyond VoIP; i.e., they must offer value-added services such as IM, audio and video content recording, and virus scanning of file transfers. Eclipse provides those services, and it also supports the applications.

Interoute and Federations
Interoute (www.interoute.com), headquartered in the United Kingdom, is the owner and operator of a pan-European voice and data network that encompasses over 53,000 kms of lighted fiber. This network is being incrementally deployed to other countries outside Europe, and it is also used to deliver a new, hosted service known as “Interoute One” to corporate customers.

Eclipse was selected as the delivery platform for this service because of the support for multimedia collaboration applications; e.g., Microsoft Office Communicator and LCS. This capability allowed Interoute to include unified communications in its hosted office offer and, as illustrated in figure 1, to enable secure UC between other companies that have implemented LCS. Inter-company communications is also facilitated by the fact that Eclipse and other SBCs are designed for peering as well as access.

MultiPath Switches and Gateways
Quintum (www.quintum.com), which is based in Eatontown, N.J., markets a range of intelligent Tenor VoIP access switching and gateway solutions that are deployed in enterprise and service-provider networks around the world. A key feature of these products is the “MultiPath” Architecture that enables easy deployment and minimal disruption. This allows Quintum’s gateways to be connected to all legacy networks, and there is no need for any PBX modification or reprogramming. Another important feature is the way the SIP proxy has been integrated in order to enable VoIP-to-VoIP switching survivability.

In addition to proving connectivity between circuit switch and VoIP networks, Tenor also acts as a VoIP demarcation point at the edge of the enterprise. The product is therefore a VoIP gateway, SIP proxy, and circuit switch, integrated in a way that provides intelligent connectivity between all VoIP and circuit devices.

This combination of functions allows Tenor to integrate new IP PBX and unified communication applications with existing enterprise legacy voice network equipment and devices with minimum disruption, thereby enabling enterprises to migrate to VoIP at their own pace. And it can also be deployed as a survivable branch office gateway in enterprise or hosted IP telephony and UC environments.

If connectivity to the IP PBX is lost, then the Tenor would process the calls, routing them between any of the devices (SIP or circuit) in the branch network as well as the PSTN. Tenor also supports branch offices with key calling features such as hold, transfer, auto-attendant, 911, and return 911 call routing.