Many industries that have traditionally relied on VME are driving to transform and modernize their systems to take advantage of new processor architectures and fabric-based system architectures as quickly as possible. This poses a challenge because system integrators and OEMs would like to make incremental changes to existing systems and not have to redesign all elements. They would like to reuse I/O that has traditionally been supported on VME, while updating the compute control core to new technologies and have them work together. Rather than selecting a single standard, the optimal solution will be provided through support by both VME and MicroTCA platforms for common, published, open software standards in terms of operating systems and middleware. It is this convergence of existing and new technologies that will be critical to the modernization of high-end systems.

MicroTCA leverages the emerging ecosystem of the Advanced Mezzanine Card (AdvancedMC) to create a new, flexible, small form-factor platform. It is important that system manufacturers and integrators understand the capabilities that MicroTCA brings to the embedded market.

AdvancedMCs were originally developed for AdvancedTCA (ATCA) platforms. ATCA has been targeted at the “aggregation” layer of the great “telecommunications network onion,” in between the outer edge “access” devices and inner “core” switching functions. Here, the priority is placed on a high compute capacity per blade, high availability, high bandwidth fabric between the compute blades and a few high-speed, high-density network I/O interfaces. And, given the investment in ATCA chassis and blades, it is important to have an ecosystem where many different solutions can be built around the same fabric (and thus the same or compatible blades).

AdvancedMCs bring further economies of scale to ATCA in the form of a more granular approach to the addition of either specialized processing elements or I/O interfaces. Adding from one to eight AdvancedMCs to an existing ATCA processing, I/O or dedicated carrier blade incrementally extends the solutions possible from a single ATCA chassis, both horizontally toward the network edge and vertically within the aggregation layer. This leverages the investment in ATCA into wider telco applications.

However, there are still environments where ATCA is simply either too large or too expensive to serve as a base architecture, or where -48 VDC is not an option. Thus, the idea of MicroTCA as an architecture was born (around the same time AdvancedMCs were first conceived), where the same pay-as-you-grow scalability could be realized in a much smaller, self-contained carrier assembly, and where, to a certain extent, the chassis form-factors (and applications) are limitless. Here, a typically passive backplane carrier can be mated with the appropriate type and number of fabric “hub” modules to provide the bandwidth, protocol and redundancy required for the application.

Six AdvancedMC form-factors of varying component height and module width have been specified, all leveraging the same high-speed, 170-pin edge connector. The MicroTCA specification allows for modular or monolithic chassis configurations from one carrier and one module to 16 carriers and 192 modules, while ensuring that modules always see the same “virtual” environment. These MicroTCA communications servers typically support two to three independent fabric interconnects on a carrier, where each fabric “port” (differential transmit/receive pair) is capable of up to 6.25 Gbits/s in each direction, and specific ports can be aggregated to form “fat pipes” with higher throughput.

PICMG has defined AdvancedMC fabric interconnect standards based on Gigabit Ethernet/10 Gigabit Ethernet (GigE/10GigE; AMC.2), PCI Express (AMC.1) and Serial RapidIO (AMC.4), along with defining storage interconnections based on SATA/SAS or Fibre Channel (AMC.3). The MicroTCA specification leverages these standards, allowing for switched and/or point-point fabrics. Current MicroTCA fabrics typically range from 1 Gbit/s (one port) to 12.5 Gbits/s (4 ports). The current aggregate carrier (switched backplane) bandwidth is around 40 Gbits/s, but next-generation hubs should exceed this; and the MicroTCA specification allows for up to 12.5 Gbits/s per port.

At present, AdvancedMC modules are available or under development for general-purpose processing (x86 & PPC), Digital Signal Processing (DSP), Digital Signaling (E1/T1/J1, OCx, DS3, etc), Serial ATA (SATA) and Serial Attached SCSI (SAS) storage, GigE/10GigE, Wireless Broadband (WiMAX), Voice-over-IP (VoIP), VGA video, and even PCI/PCI Telecom Mezzanine Card (PMC/PTMC) carriage. While the majority are focused specifically on telecommunications, more than a few provide applications in other solution spaces, such as military, aerospace, industrial and medical.