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Telecom Developers Guide to Open Telecom Platforms

CompactPCI, ATCA, AdvancedMC and MicroTCA

By Todd Wynia


Throughout the world, the requirements for new packet-based triple play and other enhanced services are driving the need for improved infrastructure. In order to satisfy that need, suppliers of telecom equipment are also looking to more flexible telecom platforms that enable them to reduce cost while speeding time to market. For many equipment providers, this means a move away from in-house proprietary systems toward open platforms, such as PICMG 2.16, ATCA, AdvancedMC and MicroTCA.

Open architecture systems reduce cost and time to market by making it easier for equipment providers to outsource a large portion of their system design and utilize cost-effective, best-of-breed off-the-shelf hardware and software components. In this way, equipment providers can streamline their engineering staffs and focus on network applications and services that offer greater value added and differentiation.

Open Platforms Evolve
CompactPCI was one of the first open platforms to peak the interest of equipment providers, particularly after adding telecom-friendly features like hot swap and a dedicated H.110 telephony bus. Hot swap enabled service providers to remove and replace individual CompactPCI blades from live shelves in the field without having to disable the shelf and disrupt overall service. The dedicated H.110 telephony bus enhanced data flow efficiency by enabling CPCI systems to acquire TDM (time division multiplexed) data, process that data, and move it between multiple blades in its native format.

What really made CompactPCI attractive to TEMs, however, was the addition of support for packet transport and system management. PICMG 2.16 (CompactPCI Packet Switching Backplane) added support for Ethernet backplane transfers, a key requirement for next-generation IP-based packet infrastructure. PICMG 2.9 added a system management framework based on the familiar enterprise Integrated Peripheral Management Interface (IPMI) model, which made it easy for remote shelf management systems to monitor and control individual blades.

AdvancedTCA Provides Next-Generation Open Framework
PICMG has continued to develop and improve the CompactPCI specification by exploring new telecom-friendly enhancements, consolidating those enhancements under the CompactTCA banner, and phasing out the use of PCI as the primary control and data plane. Collectively, these enhancements enable the blades in a CompactTCA chassis to be treated as network elements, a significant improvement over the traditional CompactPCI master/slave bus architecture.

Even as CompactTCA enhancements continue apace, Advanced Telecom Computing Architecture (AdvancedTCA or ATCA) is quickly emerging as the leading contender for telecom infrastructure applications. Adopted in January of 2003 with input from key equipment and service providers, ATCA provides a high-performance, high-density platform aimed squarely at next-generation packet networks.

AdvancedTCA is an open architecture framework for building high-performance, high-density, high-availability (five nines or greater), NEBS-compliant, 19-inch, rack-mountable telecom shelves. The foundation for ATCA is its high-speed switched fabric, which provides a peak throughput of 10 Gbit/sec per link, ten times that of PICMG 2.16 backplanes. The ATCA fabric supports a full mesh interconnect, which enhances availability by enabling each blade to simultaneously communicate with every other blade via dedicated channels. The ATCA fabric is also protocol agnostic, enabling it to support multiple packet-oriented protocols, including Ethernet, Infiniband, PCI Express, and Rapid I/O. PICMG 2.16, by contrast, specifies Gigabit Ethernet as the transport.

In addition to its high-speed fabric, ATCA provides numerous other features that are also critical for equipment providers. Its large form factor (8U) and high-power capability (200W per blade, versus 50W for CompactPCI) give ATCA the capacity to support complex functions and high-density configurations. And its redundant fabric, redundant power, and hot swap capabilities reduce susceptibility to point failures and enable individual blades to be serviced and upgraded without disrupting overall service.

One of ATCAs most attractive features for the service providers and carriers is its support for IPMI system management, which enhances availability by facilitating active monitoring and control of individual ATCA blades. IPMI utilizes an I2C-based physical interface to link chassis management with board-level FRUs (field replaceable units). Through this interface, chassis management can monitor physical system health characteristics such as voltages, fan speeds, temperatures, and power supply status. Chassis management can also utilize IPMI for automatic event notification, remote shutdown/restart, and to dynamically allocate power to individual blades, which helps optimize system-wide power consumption and cooling.

CompactPCI, through the PICMG 2.9 add on, provides a comparable management framework. The ATCA framework, by contrast, is incorporated as part of the baseline ATCA spec (PICMG 3.0), building on the PICMG 2.9 spec to provide a higher level of detail and additional IPMI commands.

AdvancedMC Modules Enhance ATCA Flexibility And Scalability
ATCA carriers can be equipped with up to eight AdvancedMC modules, which come in four sizes: half-height single-width, half-height double-width, and a full-height version of each. The field replaceable modules have escalating power limits of 20W for the smallest module to 60W for the largest module.

AdvancedMC enhances ATCA flexibility by extending its high-bandwidth, multi-protocol interface to individual hot-swappable modules. This provides TEMs with a versatile platform for building modular telecom systems that can be outsourced, designed/manufactured, stocked and spared at a lower cost. The modular architecture also reduces service provider operating expenditures by reducing the impact of component failures, and enabling service providers to scale, upgrade, provision, and repair live systems with a finer degree of granularity and minimal disruption to overall service.

MicroTCA Addresses Low- To Mid-Range Applications
The ATCA/AdvancedMC platform is an outstanding solution for many mid-range to high-end telecom infrastructure applications because of its high performance, modularity, and five nines reliability. These features, however, come with a price tag that can be too expensive for many central office, outside plant, and customer premises applications. ATCAs generous form factor is also a stumbling block for outside plant applications such as wireless base stations with tight space constraints.

To serve these low- to mid-range telecom applications with space and/or cost constraints, PICMG is in the process of developing a new specification based on the AdvancedMC platform known as MicroTCA. With ratification expected in June 2006, MicroTCA essentially eliminates the ATCA carrier, enabling equipment makers to directly utilize AdvancedMC modules in a variety of enclosures.

MicroTCA enables equipment providers to leverage the installed base of off-the-shelf AdvancedMC modules, while achieving lower cost in a smaller footprint. MicroTCA also enables equipment providers to utilize the same serial fabric interface and integrated IPMI system management used in ATCA/ AdvancedMC systems. This combination makes MicroTCA an outstanding complement to ATCA for small form factor central office and outside-plant applications like wireless base stations, WiFi/ WiMAX radio boxes, next-generation digital loop carriers, optical ADMs, and Fiber to the Curb optical network units.

The foundation for the MicroTCA chassis is the MicroTCA Carrier Hub (MCH), which provides the switched fabric and shelf management functions. MicroTCA backplanes will provide scaleable bandwidth up to 40 Gbit/sec. Using the same serial transport mechanism as AdvancedMC, MicroTCA backplanes will provide a raw bandwidth of 12.5 Gbit/sec per channel while supporting star, dual-star, and mesh topologies. Like ATCA and AdvancedMC, MicroTCA is also protocol agnostic, and supports a variety of packet-based protocols, including Ethernet, PCI Express/AS, and Rapid I/O.

To enhance availability, MicroTCA shelves support hot-swappable AdvancedMC modules, enabling service providers to replace individual modules in the field without taking the entire shelf off line. The MicroTCA backplane also provides IPMI, which enables the shelf management to monitor and control each module installed in the backplane.

MicroTCA shelves will be able to accept any standard AdvancedMC module in a variety of form factors, including half-height/single-wide, half-height/double-wide, full-height/single-wide and full-height/double-wide. A typical high-availability shelf could combine redundant MCHs and power modules with up to 12 AdvancedMC modules. MicroTCA shelves will take power from an AC main or traditional -48 Vdc telecom source, and convert it to 12V for delivery to individual AdvancedMC modules.

CompactPCI based systems can still provide a good solution for many telecom projects. However, taken together, ATCA, AdvancedMC, and MicroTCA provide a modular, scaleable end-to-end framework that addresses the full spectrum of next generation, high-availability packet-based telecom applications, from core routers and WDMs, to converged customer premises equipment. This open framework helps drive equipment costs down by enabling equipment providers to quickly develop and configure systems using affordable, off-the-shelf hardware and software components. It also reduces operating costs, providing a modular, field replaceable framework with integrated system management that enables carriers to scale, manage, and service their systems with a higher degree of granularity. IT

Todd Wynia is vice president of marketing for Artesyn Communications Products. For more information, please visit the company online at (news - alerts).

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