The Advanced Telecom Computing Architecture (also known as AdvancedTCA or ATCA) is an open industry standard for next-generation carrier grade communications equipment. It provides a modular means of converging telecom access and edge equipment functions with data centre and storage equipment functions. This ‘building block’ approach enables equipment manufacturers and users to employ the same chassis and backplane for multiple applications, significantly simplifying system configuration, lowering implementation costs and reducing time-to-market.
ATCA has steadily acquired a wide industry following since it was adopted by the PCI Industrial Computer Manufacturers Group (PICMG) in January 2003. More than 100 suppliers – including such prestigious names as Intel and Motorola – now support the architecture. These comprise a broad cross-section of telecom equipment manufacturers, board and system level vendors, computer OEMs, software companies and chassis, connector and power supply vendors. At the recent 3GSM congress in Cannes, for example, Siemens announced that its next generation mobile telecom architecture would be based on an ATCA-compliant platform, to help meet customers’ targets for system performance, reliability and reduced operating costs. And Alcatel launched an ATCA-compliant SGSN (serving GPRS support node), at the same time stating that it was adopting ATCA as its preferred standard for all future mobile and fixed network infrastructure applications, to reduce operators’ cost of ownership.
Analysts forecasts for ATCA are varied, though all agree that it will account for significant market share by 2007, with some estimating that this could be as high as US$ 20 billion – some 8% of the total telecom equipment market. The standard has already been widely adopted in the server and soft switch sectors, with the wireless infrastructure sector now set to expand – a number of wireless carriers have stated that they intend using ATCA systems to upgrade from 2.5G to 3G during the course of this year.
The physical structure for ATCA consists of chassis or shelf units available in several capacities to fit either 19 inch EIA racks or 600mm ETSI equipment racks. As shown in Figure 1, each chassis contains a backplane that interconnects vertically-mounted pluggable board or blade assemblies. High speed interconnection technology addresses the needs of next generation high performance processors -- ATCA systems are capable of switching and processing 2.5 terabits per second on a single shelf. The blades or boards are 8U (357mm) high and 280mm deep with a board to board spacing of 30.5mm (1.2 inches), and each board can support up to 200W of power dissipation on its 903cm2 (140 sq in) of area. EIA shelves can accept up to 14 boards and ETSI shelves up to 16.
Figure 1: Photo of a typical ATCA chassis, courtesy of Kaparel Corporation, a Rittal company
The high power density is achieved by means of a standardised forced air cooling system which is part of the architectural definition. Each chassis takes in ambient air at the bottom front of the unit through cooling fans (not shown in Figure 1). The air is then routed with a plenum to flow vertically up through the pluggable boards. Another plenum at the top of the chassis then redirects the air to exhaust at the back.