Standards-based communications building blocks can bring many benefits to system designs including reduced development time, cost, and lower extended lifecycle costs, while retaining opportunities for innovation. Securing these benefits when using standards-based commercial off-the-shelf (COTS) products, however, requires interoperability among elements from different vendors.

The use of pre-fabricated building blocks can be an extremely cost-effective approach to system design, especially when using off-the-shelf products that are based on open industry standards. Because standards-based blocks have broader utility than custom designs, vendors can leverage the efficiencies of volume manufacturing to reduce unit cost. System designers save development time and effort, further reducing costs as well as speeding time to market.

System development companies also gain the ability to make a more focused investment. By not having to create these standard blocks themselves, design teams free resources to concentrate on their company's unique value add to the system design. This is especially beneficial when the company does not have the resources required to create everything from the ground up anyway. Adopting standards-based design provides such resource-limited companies the opportunity to enter a market that would otherwise be closed to them.

Adopting the standards-based design approach can further reduce costs over the design's lifecycle by leveraging multi-vendor competition in creating the blocks. Competition naturally helps keep down component costs for both initial purchase and maintenance replacements. Multi-vendor competition also fosters innovation that provides designers with the opportunity to make system upgrades at low cost by simply replacing blocks.

Experience has shown, however, that the promise of standards-based design is easily undermined. The COTS offerings may include capabilities not needed in the end system, resulting in wasted resources. An even greater problem, however, is that ambiguities, allowed options, and gaps within the standards that can lead to variations among vendors' product offerings. These variations, in turn, prevent building blocks from different vendors from working with one another, despite the fact they all conform to the standard. This situation not only undermines the benefits of standards-based design, it can turn the approach into a liability. Interoperability among multiple vendor products, then, is an essential requirement of standards-based design.

Communications Standards Ecosystem

Despite these risks, the benefits of standards-based design are so compelling that the communications industry has gone to considerable effort to foster the approach and develop the appropriate standards. The standards now available address all elements of a communications system design (See Figure 1). One set of standards addresses the design of the communications platform hardware. Another defines the operating system software that runs on the platform. Further sets of standards address the hardware/software interface, applications programming interface, and middleware for high-availability operation and essential system management services.

Figure 1. All the fundamental hardware and software elements of a communications system design, including interfaces between elements, have open industry standards defining them.

These standards do not all reside under one roof, however. Three different groups are actively involved in the definition of standards, with additional groups providing guidance and coordination. The hardware platform standards, for example, fall under the auspices of the PCI Industrial Computer Manufacturers Group (PICMG). The PICMG has defined the Advanced Telecommunications Computing Architecture (ATCA) and the derivative MicroTCA platforms, developing standards for card cages, power systems, and plug-in modules including aspects such as system management, cooling, and inter-module communications. The organization has also defined a mezzanine card architecture (AdvancedMC) that both modularizes the design of ATCA boards and serves as the base board for MicroTCA platforms.

The operating system building block is the domain of the Linux Foundation. This organization has two roles. One is the standardization of the Linux operating system for general computing use. The other is to define a carrier-grade Linux that meets the real-time, fault-tolerant, high-availability needs of communications system operation.

Because many of a communications system's functional requirements are well established and common among all systems, an opportunity for standards-based system software has arisen. One of the key software requirements is that system operation be highly reliable as well as fault tolerant so that systems maintain operation 99.999% of the time. The Service Availability Forum (SA Forum) has defined the functional requirements of a software base, called Service Availability Middleware that will provide this capability and created the OpenSAF reference implementation. The SAForum has also defined standards for the middleware's interface to other system elements--the Hardware Platform Interface, the Applications Interface Specification, and the Systems Management Interfaces.

Each of these standards-defining organizations arose independently from the vendor community serving communications system developers. In order to ensure that these independent efforts closely reflect developer needs the SCOPE Alliance, a consortium of network equipment providers, arose. The SCOPE Alliance has created profiles that define the functional requirements on platforms and systems built from standard hardware and software blocks. These definitions give the standards bodies a target for their efforts.

The Role of the CP-TA
Ensuring that these various standards-based hardware and software building blocks will all work together once assembled falls outside the scope of any one standards organization, however. To fill that gap, the Communications Platforms Trade Association (CP-TA) arose. The CP-TA seeks to accelerate the adoption of standards-based COTS for communications system design, while preserving the developer's freedom of choice among vendors, by tightening and clarifying standards to address interoperability issues.

Where the SCOPE Alliance provides the standards organizations with concrete targets, the CP-TA works to ensure that the results all mesh together without requiring substantial integration effort. The CP-TA's unique value is that it bridges between organizations to keep the standards compatible, defines compliance levels that resolve potential interoperability issues, and provides tools and test procedures that validate those compliance levels.

In addressing system interoperability issues, the CP-TA has focused on three main domains: thermal, data transport, and system manageability. The domains represent what experience has shown to be the most problematic issues in building systems from standards-based building blocks. Thermal issues, for instance, include the presence of hot spots on one board that can affect adjacent boards and how board designs affect the flow of cooling air in a chassis, topics not addressed in the standards that can create problems during system integration. Data transport and system manageability issues arise as the result of vendors choosing different allowed options or having differing interpretations of the standards, also creating system integration challenges.