A white paper from IDT clarifies high-speed interconnect technologies for communications applications
To obtain higher bandwidths, designers of communications and networking equipment, servers and storage systems are rapidly converting from parallel bus architectures to serial types. Self-clocking serial bus structures eliminate skew between data and clock lines, allowing faster data rates and more bandwidth per pin, while also enabling highly scalable and cost-effective solutions.
Various interconnect and serial switching I/O standards now exist or are in development that can be used to implement the bus structures. There is no universally superior solution and each of the alternatives has relative advantages and liabilities. The optimum choice depends on the specific application and may change over time, since the technology situation is evolving rapidly.
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| PCI Express devices |
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In the enterprise server and storage arena, PCI Express (PCIe) is already widely accepted as the successor to PCI. OEMs will lead adoption of PCIe technology, delivering prototype PCIe hardware over the next year. A bit further into the future, InfiniBand and the Advanced Switching Interconnect (ASI) protocol will vie for acceptance over the next few years.
InfiniBand is tailored specifically towards high-end computing applications such as data center clustering. Its software-intensive protocol and complex addressing and routing scheme are intended for chassis-to-chassis interconnects that scale to hundreds or thousands of nodes. Substantial protocol overhead is required and there is minimal congestion-management support.
ASI aims at communications applications that require a “data lane fabric” and delivers superior performance and value relative to Ethernet. It provides QoS, high reliability, excellent performance and extensive scalability. ASI supports multi-protocols for wireless area network (WAN) applications and offers a lossless fabric that allows the system to retain control over its traffic-management architecture. From a pure performance perspective, ASI offers a clear roadmap to 10 Gbits/s and beyond.
Another standard, RapidFabric, a planned extension of Serial RapidIO, is currently under development. RapidFabric should be the appropriate solution for applications with unified and homogeneous RapidIO endpoints. By contrast, ASI is well positioned as a backplane switch fabric protocol strongly suited for multi-protocol and high availability requirements.
Devices matched to applications
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| SPI-4 devices |
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IDT, supplier of semiconductor solutions that accelerate innovation, strives to meet customers' needs with the right standards-based products. The company has been aggressively driving products and ecosystem development for its standards-based switching thrust, featuring PCIe and ASI. Moreover, the company recently announced that it is developing switching devices for board-level applications that will utilise Serial RapidIO.
According to Phil Bourekas, vice-president of worldwide marketing for IDT: “Our strategy is to leverage appropriate standards for various applications. More specifically, we will offer a range of high-performance devices optimized for specific design requirements.”
Free white paper
A 14-page IDT white paper, "Standards-Based Switching: New Options in High-Speed Interconnect Technology," helps system engineers better understand the strengths, limitations and application suitability of the various serial I/O schemes. It discusses market trends; tabulates the fit of nine standards in inter-chassis, backplane and on-board applications; and makes key protocol comparisons. It also offers suggested usage models and provides application examples. Click here to download this free white paper.
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