ATCA is the most promising architecture to substantially enhance the performance and capability of existing control and data acquisition systems as it is designed to handle tasks such as event building, feature extraction and high level trigger processing. It is the first commercial open standard designed for high throughput as well as availability (HA). The high throughput features are of great interest to data acquisition physics, while the HA features are attractive for experiments requiring a very high up-time.
The PICMG 3.0 Advanced Telecommunications Architecture (ATCA) standard was originally conceived to specify a carrier grade-based system infrastructure for telecommunications. It was designed from ground-up for high availability (redundant power supplies, shelf management of temperatures and fans …) and scalability.
Compared to the VMEbus which was conventionally used in data acquisition systems, the ATCA standard offers advantages especially with respect to communication bandwidth and shelf management. The ATCA carrier-blade form factor supports well-balanced systems, delivering teraOPS of processing power in a single sub-rack. The architecture is flexible as to the types of processors that can co-exist in the system. One of the most critical aspects of implementing the ATCA architecture is the ability of high-performance blades to communicate with each other, so that vast quantities of data can be moved from board to board through the switch fabric within an ATCA system.
| ATCA | VPX | cPCI Express | |
|---|---|---|---|
Dimensions |
8U |
3U and 6U |
3U and 6U |
Nr analogue channels |
32 |
16 |
16 |
Fabric |
Agnostic |
Agnostic |
PCI Express |
Backplane |
Full-mesh |
Full-mesh |
Star |
RTM |
Yes |
Yes |
Yes |
Mezzanines |
Yes |
Yes |
Yes |
Power dissipation/slot |
200 W |
Shelf |
Shelf |
Redundant power |
Backplane |
External |
External |
Redundant cooling |
Yes |
No |
No |
Hot swap |
Yes |
Yes |
Yes |
Shelf management |
Redundant |
IPMI |
IPMI |
EMC shielding |
Yes |
Yes |
Yes |
Availability |
99.99% |
- |
- |
Foreseen main |
Telecom |
Military |
Industry |
Table I: Comparison of technical features between ATCA and its direct competitors |
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The ATCA base specifications define Shelves (sub-rack), Boards (SBC, IO, Hub/switching, Mezzanines Carrier), Mezzanines (AMC, PMC) and Management interface sharing a common backplane with interconnections based on a full mesh of serial gigabit communication links.
Each slot can be interconnected to all others through x1, x2 and x4 links with a maximum throughput capacity of 800 MByte/s. By choosing the correct links, it is possible to have more than one controller on the ATCA shelf, each controlling a set of ATCA digitizer modules.
The ATCA redundancy scheme permits to have two equal sets of cards installed on the shelf and in case of failure of the operating set, the second one can take over its functions. ATCA is also capable of hot-plugging of cards thus allowing continuous operation and maintenance.
Supported communications protocols are the Advanced Switching Interconnect (ASI), PCI Express (PCIe), Gigabit Ethernet (GbE), Serial RapidIO (SRIO), Infiniband or other PICMG 3 compliant standards. Each slot is interconnected to all others through x1, x2 or x4 links with a maximum real throughput capacity of ~800 MByte/s (10 Gbit/s per link – 25 Gbit/s per link supported).
ATCA platform highlights:
- Scalable shelf capacity to 2.5Tb/s;
- Each slot is interconnected through up to four 2.5 Gb/s links with an actual throughput capacity of ~800 MByte/s per link;
- Scalable system availability to 99.999%;
- Multi-protocol support for interfaces up to 40 Gb/s;
- Robust power infrastructure (distributed 48V power system) and large cooling capacity (cooling for 200W per board);
- High levels of modularity and configurability;
- Ease of integration of multiple functions and new features;
- The ability to host large pools of DSPs, NPs, processors and storage;
- The ability to host multiple controllers and storage on a shelf (blade servers and DSP farms);
- Advanced software infrastructure providing APIs and OAM&P;
- High security and regulatory conformance;
- Supports 14 slots shelves in 19” cabinet;
- Large enough board for low cost;
- Reliable, full redundancy support;
- Reliable mechanics (serviceability, shock and vibration);
- Hardware management interface.
AdvancedTCA Standards:
- PICMG 3.0: Base Specification wich covers mechanical, power, cooling, interconnect of the AdvancedTCA family of specifications;
- PICMG 3.1: Ethernet and Fiberchannel Transport;
- PICMG 3.2: InfiniBand Transport;
- PICMG 3.3: StarFabric Transport;
- PICMG 3.4: ASI and PCI Express Transport;
- PICMG 3.5: Serial RapidIO Transport.
Additional ATCA related specifications:
- Advanced Mezzanine Card (AMC);
- MicroTCA.