June 1999

MEDIATION MEDICATION

BY STEVE KELLY

Public networks are in transition, and it's causing headaches. Stress and strain are affecting the budgets and facilities of new and incumbent service providers alike. PSTN operators are straining to reduce the cost of delivering voice services while providing enhanced services and accommodating new and growing data demands. Similarly, operators of public packet-switched data networks (PSDNs) are under pressure to add toll-quality voice and video to their portfolios. And both of these networks must accommodate a bewildering array of access interfaces: ISDN, frame relay, wireless, ATM, DSL, etc. Service providers are looking to relieve this stress by implementing converged network infrastructures that reduce operational complexity and costs. These multiservice platforms also improve customer service by delivering integrated, one-stop shopping and billing, and by employing software-configurable services that put self-provisioning control into the customer's hands. The shift to integrated networks is driving the need for a new generation of carrier equipment that "mediates" between the various circuit- and packet-based access and backbone services.

EASING TRANSITIONAL HEADACHES
The ubiquity of the PSTN means that it will continue to be a viable - though evolving - network platform for many years to come. For carriers to achieve their goals and compete effectively in the 21st century, their switching architectures must minimize the headaches associated with the migration of the PSTN from a centralized, circuit-switched platform to a more distributed, packet-switched model. Easing this transition involves two distinct but related requirements: a physical platform with a small, cost-effective footprint, and a network-unifying function within the platform called service mediation.

Mediation combines multiple, software-based gateway functions within a single device. It allows the delivery of phone calls and the extension of custom local access special services (CLASS) -built around SS7 and other Advanced Intelligent Network (AIN) standards - from the PSTN to the PSDN, regardless of the access or backbone protocols used. In this way, the gateway function provides an excellent migration path for the legacy PSTN. It does not discriminate in favor of particular technologies. Instead, this approach allows service providers to make use of the backbone network of their choice.

Combining the benefits of both the existing PSTN and newer data infrastructures is a key benefit of service mediation. Providing "any to any" mediation within one platform is less expensive than building separate networks or installing and managing multiple, individual gateways for each service offered.

Mediation-based switching platforms are generally deployed in a distributed fashion at the edges of carrier networks. By providing conversions between networks at these interconnection points, these platforms make it feasible from an economic and management standpoint for new entrants to set up shop in the converging telecommunications and data networking market. Such platforms also help incumbents transition their legacy networks to support new services without going to the expense of overhauling their network infrastructures.

AFFORDABILITY AND INNOVATION
While the PSTN has grown into a highly reliable and nearly ubiquitous network, the pace of innovation in data communications has far exceeded that of voice networks. The capacity of data networks has been doubling every 12 to 18 months, and in the highly competitive data communications market, differentiation has become the key to survival. The result? Microprocessor advancements have increased the rate of innovation exponentially and lowered the cost of data communications infrastructure dramatically.

The PSTN is making the transition to this model. The PSTN's monolithic, mainframe-based architecture, while highly reliable and well-suited to vanilla voice services, will no longer suffice for competitors who must be nimble, innovative, and quick to market to survive new competition and fast growth. These platforms are too expensive (several million dollars apiece) for most providers to deploy quickly in many markets, they do not provide a flexible development platform, and they are not upgradable to newer technologies.

By contrast, the new mediation-based PSTN switching platform is small and transportable and generally costs an order of magnitude less than the Class 5 switch at the core of the PSTN today. These characteristics make possible a scenario, for example, where a carrier might purchase a single Class 5 and extend its functionality to many markets using the smaller, less expensive mediation platform.

This shift in switching platforms is analogous to the PC-to-mainframe client/server computing model. Smaller, less expensive platforms can be affordably deployed in more places and perform functions on their own while also tapping into the "server" for some functionality. In addition, smaller, software-configurable platforms are more conducive to application development. Just as there was a mass migration from "big iron" to PC development platforms in the 1980s, the new network development platforms hold the promise of breaking down barriers to innovation, in part by easing the cost and technology burdens of prototyping.

Some of these applications include innovative call center services. Gateways between Web sites and PSTN-based call centers, for example, can enable the delivery of Web-based call centers with integrated browsing and "click-to-talk" capabilities, where Internet users can click a button on a Web site to talk to a call center operator for additional information.

COST SAVINGS AND INTEGRATED MANAGEMENT
The mediation function also delivers cost savings directly to the service provider, since it becomes possible to design an integrated network rather than requiring carriers to build multiple networks or run multiple gateways. In addition, the blending of legacy networks with newer packet-switching functions lets incumbents continue depreciating their existing equipment while incrementally adding on new services that come into demand. The new platform also includes a set of rules to manage access to telecommunications and data communications application and services databases. This means that carriers can plug the devices into their existing management and operational systems to retain those system and human resource investments.

SOFTWARE PROVISIONING
By supporting a mix of frame relay, PSTN, ATM, and other types of ports all within a single box, multiservice platforms enable software-driven provisioning systems. Software-based provisioning systems allow service providers to make network changes quickly and also offer new value to end customers.

For example, imagine the value to corporate customers who can easily implement sophisticated hunt groups, call routing, and bandwidth provisioning to self-manage voice and data bandwidth allocations. Allowing users to better define and manage services through an easy-to-use interface will give a competitive advantage to carriers when delivering 21st century telecommunications services.

THE BOTTOM LINE
By taking advantage of mediation between the public voice and data networks, carriers can increase their flexibility in defining and provisioning services, which leads to significant advantages in time-to-market with new services, cost containment, and capacity management. Service mediation provides a cost-effective migration path and economic motivation for both incumbent and emerging carriers to invest in next-generation switches that extend the use and life of the existing PSTN infrastructure while enabling new services delivered from packet-switched environments.

The next-generation platforms allows carriers to quickly expand to new markets while delivering a richer choice of voice and data services to customers - with no discrimination on the access or backbone network used.

Steve Kelly is co-founder of Castle Networks, a privately held company focused on delivering carrier-class voice and data convergence equipment for 21st century telecommunications networks. Castle Networks is building next-generation infrastructure equipment that will help to cost-effectively integrate the PSTN and the PSDN. For more information, please visit their Web site at www.castlenetworks.com.

The Castle Networks implementation of a service mediation platform addresses the range of affordability and scalability issues facing voice service providers. The company's first product, the C2100, is a flexible, distributed system that connects the circuit-switched PSTN and its associated intelligent calling features to emerging IP and ATM packet-switching networks. The bridging of these disparate network types enables calls to originate on one network and terminate another for any-to-any connectivity.

We had a chance to speak with Castle Networks regarding the C2100, and here are some excerpts from that interview:

CTI: A traditional carrier must be concerned with providing reliability and gaining as much value as possible from its existing legacy equipment while considering offerings of enhanced services and functionality. How does the C2100 address these concerns?

Castle Networks (CN): The C2100 blends the strengths of traditional telephone equipment with the cost and performance benefits of distributed processing. The device unbundles voice switching from expensive, centralized Class 5 switches and distributes the processing onto multiple, less expensive platforms deployed at the edges of service provider networks, where interconnection with other networks takes place. The C2100 has been engineered with redundant components to deliver the 99.999 percent network availability that voice customers have come to expect.

CTI: What about scalability concerns, for both traditional and next-gen providers?

CN: To ease network scalability as service providers' customer bases grow or new services emerge, the C2100 is modular in nature. Service providers can add up to 15 channelized DS3s per chassis, and multiple chassis can be clustered to form a system that scales to more than 240,000 DS0s. This translates into a platform that scales from tens to millions of connections.

CTI: In trying to mediate between various networks, you are addressing service providers and carriers who probably have a broad range of skill levels and backgrounds. What accommodations are there for this disparity in the C2100 platform?

CN: A management mediation system in the platform contains different user interfaces to accommodate personnel with varying skill sets. The management system will also plug into legacy operational support systems (OSSs) so that service providers can continue to leverage their existing investments in management platforms and resources.

With its C2100 platform, Castle Networks has addressed the voice/data convergence issue from the ground up. Both PSTN operators wishing to add data services to their portfolios and data network operators wishing to expand into voice services can migrate to new, multiservice networks at the pace that makes business sense for them using the network technologies of their choice.