Telecom is rapidly evolving as service providers build out their broadband packet networks to offer enhanced wireless, data, video, and VoIP services. Most TEMs have historically built virtually everything in-house. As deregulation has made the service and equipment landscape increasingly competitive, delivering home-grown equipment in a timely, cost-effective fashion has become much more of a challenge.
By utilizing open platforms like AdvancedTCA, AdvancedMC, and MicroTCA, suppliers to TEMs can now offer a wide range of system level hardware and software that makes outsourcing both convenient and cost effective.
What is ATCA?
Defined in January 2003, AdvancedTCA is an open architecture framework designed for building high performance, high density, high availability, rack mountable telecom shelves. ATCA defines the mechanical form factor, electrical interfaces, switched fabric configurations, transport protocols, and system management interfaces for the ATCA chassis, ATCA plug-in cards, and shelf management controllers.
Because they utilize multiple independent point-to-point serial links for blade-to-blade communications, TEMs prefer switched fabrics over general purpose parallel buses. These point-to-point connections increase availability by making the overall system less vulnerable to individual blades or link failures. Theyre also more scalable, making it easier for TEMs to squeeze extra bandwidth out of existing platforms.
ATCAs hot-swappable switched fabric provides a peak throughout of 10 Gbit/sec per link and supports a full mesh interconnect, which maximizes availability by enabling each blade to simultaneously communicate with every other blade via dedicated channels. The ATCA switched fabric is also protocol agnostic, enabling it to support multiple packet-oriented protocols, including Ethernet, Infiniband, PCI Express, and Rapid I/O.
In addition to its high speed fabric, ATCA provides a number of other features that are critical for TEMs. Its large form factor (8U) and high power capability (200W per blade) give it the capacity to support complex functions and high density configurations. And its redundant fabric, redundant power, and hot-swappability reduce susceptibility to point failures and enable individual blades to be serviced and upgraded without disrupting overall service.
One of the greatest contributors to overall CAPEX (define - news -alerts) and OPEX savings in ATCA systems is ATCAs redundant Intelligent Platform Management Interface (IPMI) system control framework, which facilitates active monitoring of and control over individual ATCA blades. This capability is especially important for high-density systems utilizing large numbers of high-performance processors, where thermal control and power management are major concerns.
IPMI utilizes an I2C-based physical interface known as the Intelligent Peripheral Management Bus (IPMB) to link chassis management with board-level FRUs (field replaceable units). IPMI can be used to monitor physical system health characteristics such as voltages, fan speeds, temperatures, and power supply status. It can also be used for automatic event notification and remote shutdown/restart. This information simplifies system design by enabling TEMs to monitor, test, and diagnose systems at the blade level during the development phase. It also enhances availability by enabling IPMI technicians to isolate problems faster with a finer degree of granularity, thereby reducing mean time to replacement (MTTR).
Modularity & Flexibility
AdvancedMC is a field replaceable mezzanine interface that enhances ATCA flexibility by extending ATCAs high bandwidth, multi-protocol interface to individual hot-swappable modules. The resulting fabric gives TEMs a versatile platform for building modular telecom systems that can be outsourced, designed, manufactured, stocked and spared at lower cost. Modular ATCA/AMC fabrics also reduce operating costs by enabling service providers to scale, upgrade, provision, and service their systems with a finer degree of granularity.
AdvancedMC provides a high speed, protocol-agnostic, serial packet interface with up to 21 I/O channels, each supporting data transfer rates of 10 Gbit/sec per channel. AdvancedMC modules are hot-swappable, enabling service providers to replace individual modules in the field without taking entire ATCA blades off line. They offer high power handling capability (currently up to 60W per module), which enables TEMs to implement complex functions at the module level. They also provide an IPMI interface, which enables shelf management to monitor and control individual modules residing on ATCA blades.
ATCA carriers can be equipped with up to eight AdvancedMC modules, which currently come in four sizes: half-height single-width, half-height double-width, and a full-height version of both. The modules have escalating power limits of 20W for the smallest module to currently 60W for the largest module. This mechanical flexibility enables designers to partition their blades for maximum scalability, upgradeability, and field serviceability.
Reducing Carrier Expenses
AdvancedMC facilitates a modular approach to ATCA blade design that greatly reduces time to market and cost. By using AdvancedMC, TEMs do not need to develop a custom blade for each application. Instead, they can create application-specific blades by combining a generic ATCA carrier with generic AdvancedMC components such as network interfaces, control processors, network/signal processors, and mass storage devices. Because the ATCA blade and modules are generic, they can be reused across multiple applications, thereby reducing design time and production cost. The generic nature of the blades and modules also makes them easier to outsource or purchase off-the-shelf, further reducing design time and cost.
Modular, field-replaceable ATCA/ AdvancedMC systems are also easier and less expensive to scale and upgrade, reducing equipment costs by enabling carriers to deploy the minimal hardware needed to service their subscriber base. With AdvancedTCA/AdvancedMC, TEMs can stock a single generic carrier board that spans several products, along with the handful of generic I/O, mass storage, control, and signal processing modules needed to configure that carrier for specific applications.
Because they are field replaceable, ATCA/AdvancedMC systems can tolerate failures to individual blades/modules with minimal disruption to overall service. Modular ATCA/AdvancedMC blades also reduce provisioning cost by enabling service providers to scale and provision their systems according to actual demand.
MicroTCA tackles Small-Form-Factor Applications
The same capabilities that make AdvancedMC attractive as a mezzanine architecture make it equally attractive as a blade-level specification for MicroTCA systems. Its hot-swap capability enhances availability by enabling live systems to be serviced and upgraded in the field. Its large form factor and high power capability make it ideal for implementing complex functions. Its high bandwidth, protocol-agnostic packet interface provides an ideal interconnect for linking multiple modules in a chassis. Its IPMI interface facilitates centralized, fine grain monitoring and control. And its flexible form factor makes it possible to create mechanical MicroTCA chassis packaging options that are optimized for particular applications.
PICMG performed the first physical MicroTCA demonstration in June 2005 using a 2U/300mm/19 rack based system. The system simulated a wireless application servicing millions of subscribers. Final approval for the specification is expected in May 2006.
In some ways, MicroTCA is a repackaging of modular ATCA/AdvancedMC blades for small form factor, cost sensitive applications. ATCAs large form factor, though ideal for building high density central office telecom infrastructure equipment, precludes its use in many outside plant and enterprise applications with tight size constraints. High cost also hampers the use of ATCA solutions in many outside plant, enterprise, and customer premises applications. ATCA carriers equipped with AdvancedMC modules have an added cost premium, as the carriers must be equipped with expensive card-cage-style connectors in order to house field replaceable AdvancedMC modules.
MicroTCA reduces size and cost by eliminating the ATCA carrier and enabling AdvancedMC modules to be used directly in a variety of compact, low cost enclosures, from standalone pico cells, to standard rack mount systems. The OEM production price for a baseline MicroTCA system, including a MicroTCA chassis, switching hub, and power module, is projected to range from $1,500$2,000.
To accommodate a broad range of applications, MicroTCA is designed with scalability in mind. In addition to its scaleable packaging and power options, MicroTCA provides scaleable aggregate bandwidth from one to 650 Gbit/sec, and scalable availability ranging from three nines (.999) to five nines (.99999).
MicroTCAs compact format, low cost, and low power consumption make it a perfect complement to ATCA for small form factor central office and outside plant applications, like wireless base stations, digital loop carriers, optical ADMs, and Fiber to the Curb optical network units. Some also see a role for MicroTCA in enterprise networking applications such as workgroup routers, modular servers, and SAN storage boxes.
Virtual Carrier Environment
A MicroTCA enclosure acts as a virtual carrier, emulating the ATCA carrier environment. The virtual carrier provides the interconnect, power conversion, clock distribution, and system management functionality need to support up to 12 AdvancedMC modules. Some of this functionality may be implemented using components integrated as part of an active backplane. However the most cost effective approach is to implement this functionality using a dedicated virtual carrier management (VCM) module. Systems requiring high availability would deploy these VCM modules in redundant pairs in order to eliminate the VCM as a single point of failure.
The virtual carrier interconnect fabric provides the main connectivity among AdvancedMC modules in a MicroTCA enclosure. The VCM module acts as a dual-star hub, providing a central switch and high speed lanes to each module. The half-duplex, serial lanes provide a scaleable bandwidth ranging from 3.125 Gbit/sec to 12.5 Gbit/sec per channel, compatible with the data rates supported by individual AdvancedMC modules.
MicroTCAs small size, low cost, field replaceablity, and scaleable performance, coupled with its ability to utilize off-the-shelf AdvancedMC modules and ATCA/AdvancedMC infrastructure, make it an ideal platform for low- to mid-range telecom applications. Together with ATCA and AdvancedMC, MicroTCA provides an end-to-end framework that addresses the full spectrum of high availability telecom applications, from core routers and WDMs, to converged customer premises equipment. IT
Stuart Jamieson is director of advanced technology for Artesyn Communications Products, and he is also currently the draft editor for the MicroTCA PICMG standard. For more information, visit Artesyn online at www.artesyncp.com (news -alerts).