Against this evolving network landscape, a new network architecture—one that will blend the PSTN and PSDN—is emerging.

This shift is strikingly similar to the change that occurred in corporate information processing during the last decade. Economics and breakthrough technology combined to alter the data networking architecture completely. Instead of networks based on large, centralized, expensive mainframes and dumb terminals, today's distributed networks are made up of low-cost, smart desktop computers linked together. This transformation has permitted applications to be pushed closer to the end-user, reducing overall cost while greatly enhancing system flexibility and functionality (see Figure 2).

Figure 2. Distributed Control Architecture

In other words, this new generation of low-cost, open switching platforms has the potential to transform the telecommunications service market in the same way that the desktop personal computer (PC) changed the corporate computing landscape. Large, centralized, Class-5 proprietary switches will continue to play a significant role in the network, but distributed, open, and progammable Class-5 access and enhanced services platforms will play a dominate role in altering the network landscape.

The Missing Link

Instrumental to the success of this transformation is a new next-generation architecture, purposely constructed to provide the missing link between the PSTN and the PSDN (see Figure 3).

Figure 3. The Missing Link in Network Convergence

This next-generation switching architecture represents an entirely new approach to delivering services that is specifically designed to accomplish the following services:

• deliver robust switching functionality at a cost that is an order of magnitude lower than traditional, proprietary Class-5 switches
• distribute switching functionality to the edge of the network
• protect existing investments by supporting all current analog and digital network standards, interfaces, media, and service elements
• reduce the number of network elements by combining a range of telephony, application, and service-delivery functions
• enable new service creation through programmability and the flexibility of an open application programming interface (API)
• provide a high degree of scalability, enabling network operators to expand their subscriber base rapidly and cost-effectively
• promote extensibility through open architecture design and, thus, take advantage of future technological advances
• redefine true, carrier-class design for maximum fault tolerance and zero downtime
• reduce operating costs by employing advanced remote maintenance and diagnostics capabilities.
• increase revenues by shortening time to market, reducing upfront costs, and providing remote management capabilities

Clearly, this approach represents a dramatic departure from traditional switch architecture. The differences in a side-by-side comparison are immediately apparent (see Table 1).

Traditional Class-5 Switch	Next-Generation Switch
$3 million startup	$100,000 startup
Hub and spoke switching	Distributed switching
Remote Switching Modules (RSMs) and Digital Loop Carriers (DLCs)	ATM and/or IP core switching and backbones
Adjunct boxes for enhanced services	Class-5 access device with integrated enhanced and data services
Separate data network boxes

Table 1. Traditional versus Next-Generation Switch