Vendor Network Architectures�Part XXXIX: NexTone Communications, Inc.

NexTone Communications, Inc., headquartered in Gaithersburg, Maryland provides intelligent switching solutions to the carrier and large enterprise market. Their products are characterized as session controllers, systems that address issues of session routing, call admission control, signaling interoperability, service quality, and network security. These controllers provide intelligent, secure, next-generation Internet Protocol (IP) and IP Multimedia Subsystem (IMS) network interconnects that enable new revenue streams from VoIP and multimedia services.

These technologies enable a common way to exchange, secure, monitor, control, and bill for voice and multimedia sessions flowing through IP networks, giving IP network operators instant connectivity and quality compatibility to rapidly add new revenue-generating services including real time data, video and interactive gaming, and fixed-mobile convergence.

More than 500 service providers and enterprises worldwide use NexTone’s solutions to dramatically lower capital expenditures and deliver ongoing operational efficiencies including reduced interconnect “turn-up” time and simplified network operations. NexTone customers, using the IntelliConnect System, carry over 50 percent of the world’s international VoIP traffic.

Established in 1998, NexTone currently has 156 employees and nine major offices worldwide.

The session controller is a system that is complementary to a softswitch, but one which deploys different technologies. The softswitch is a voice-centric system that routes calls between the Public Switched Telephone Network (PSTN) and an IP network. In contrast, the session controller is focused on a much broader set of real-time services, including voice, video, multimedia, and instant messaging, which are delivered to packet networks using the Session Initiation Protocol (SIP), defined by the Internet Engineering Task Force (IETF), or the H.323 protocol, defined by the International Telecommunications Union – Telecommunications Standard Sector (ITU-T). Both of these technologies must coexist to provide a bridge between the PSTN and IP networks, however, session controllers treat a softswitch (and its associated media gateways) as an IP endpoint that can service voice calls.

The session controller provides routing and control operations to manage real time traffic flows between IP networks. These functions are typically distributed between session controllers deployed at different points within a carrier network. The Edge Session Controller (ESC) is deployed at the edge of the network, and controls a carrier’s connections to their enterprise customers and other service providers. The ESC provides these edge functions, including call admission control, network security, and signaling interoperability. The Core Session Controller (CSC) is deployed at the core of the network. The CSC provides network functions, including session routing and service-level call admission control, that is, the policies that may limit the number of calls that can originate from one particular carrier.

NexTone’s products, all part of their IntelliConnect System, are software based which are deployed on industry-standard hardware platforms such as Sun and Intel servers. These products are partitioned into three functional areas. The Real-time Session Manager, or RSM, operates at OSI Layer 7, and centrally controls all of the edge devices. The RSM operates in the network core and automates operational tasks, such as session management and performance measurement, provisioning, reporting, and call detail recording. The Session Switches operate at OSI Layer 5, and provide a signaling subsystem, including session control, policy enforcement, security, and interworking functions. Two switches are available: the MSX, which is scalable from 500 to 30,000 sessions and provides for session routing, session border control, and SIP registration functions; and the IMX, which is a SIP-only product that provides for IP Multimedia Subsystem (IMS) interconnect. The Session Border Controller, or SBC, operates at OSI Layers 3 and 4, and provides a media routing engine, plus media processing and security functions. It also provides protocol interworking between SIP and H.323 endpoints, and media transcoding, supporting the G.711, G.723, G.726, and G.729 codecs.

Further details on the NexTone architecture and products can be found at Our next tutorial will continue our examination of vendors’ architectures.

Copyright Acknowledgement: © 2006 DigiNet ® Corporation, All Rights Reserved

Author’s Biography
Mark A. Miller, P.E. is President of DigiNet ® Corporation, a Denver-based consulting engineering firm. He is the author of many books on networking technologies, including Voice over IP Technologies, and Internet Technologies Handbook, both published by John Wiley & Sons.

Latest Articles

Follow Us On Social Media

Explore More