The early silicon sets the stage for the first servers using this 2.5-Gbit/second, point-to-point interconnect technology. Those servers are expected to hit the market late this year.

"The availability of silicon is a critical milestone for Infiniband," said Vernon Turner, an analyst with International Data Corp. Turner said IDC expects 100,000 servers built around the Infiniband architecture to ship this year, skyrocketing to 3.5 million servers in 2004.

Internet service providers are the poster-boy customers. By moving beyond the shared-bus approach of PCI to Infiniband's switched-fabric scheme, Internet data centers will be able to add servers more quickly and easily, said Philip Brace, a director of product marketing for Intel.

Other elements of the Infiniband infrastructure are emerging from various development laboratories. Vieo Inc. (Austin, Texas), a software startup dedicated to Infiniband software, said its engineers hope to demonstrate a working Infiniband software suite on a server at the Intel Developer Forum in San Jose, Calif., starting Feb. 26.

At that time, Agilent Technologies will release three products for testing the server architecture, including a family of debug and verification tools, a digital communications analyzer and a logic-analyzer probe.

Intel last week said it is shipping samples of the three main types of Infiniband silicon to major customers. The Infiniband host channel adapter (HCA) for servers went to Compaq Computer, IBM and others; Infiniband switch ICs, needed for storage routers, were sent to QLogic and Crossroads Systems; and the target channel adapter (TCA) silicon for storage and networking devices was sampled to Adaptec and LSI Storage Systems.

While Intel plans to begin commercial shipments in the second half, Mellanox Technologies announced immediate availability of its InfiniBridge family of devices, including HCA, switch and TCA devices and software.

Chief executive officer Eyal Waldman said the chips support both 2.5-Gbit/s (1x) and 10-Gbit/s (4x) links. The HCA device, which includes an integrated eight-port switch and an Infiniband-to-PCI bridge, is packaged in a 516-pin PBGA and is priced at $196 in quantities of 10,000.

The Infiniband servers coming to market later this year probably will start with the 1x speed, which is 2.5 Gbits/s full duplex, and move quickly to 4x, or 10 Gbits/s, an industry source said. The Mellanox silicon supports the 4x speed in its initial implementation.

The company's InfiniBridge channel adapters and switches incorporate a nonblocking, full-wire-speed switch architecture that supports multiple "virtual lanes" for data and control, as well as a dedicated management lane for quality-of-service, bandwidth allocation and latency guarantees.

Mellanox engineers developed a software-transparent bridge between multiple Infiniband links and a 64/32-bit PCI bus operating at up to 66 MHz, allowing for backward compatibility of software designed to run in PCI-to-PCI bridges. The development kit includes schematics, layout, bill of materials, signal-integrity simulation and other software.

Preserving the legacy software costs associated with PCI was one of Mellanox's main targets. "InfiniBridge lets system vendors leverage their investment in PCI-based network adapter cards and PCI-based software," Waldman said. "This allows system vendors to migrate from PCI to Infiniband at their own pace, without abandoning their investment in legacy technology."

Meanwhile, Mellanox, which does much of its development in Israel, has received second-round investments from Intel. "Intel is an investor, and we collaborate with them on projects, but they are also a potential customer — and a competitor," Waldman said. In that regard, Mellanox's ace in the hole is that it has silicon now, he said.

Intel's Brace said it was "premature" to discuss details of the Intel silicon because the devices may be configured differently for major customers, based on input during the sampling stage. Engineers at Intel's Portland, Ore., facility are doing much of the Infiniband IC design work, supported by Intel design teams in India and elsewhere.

The HCA and TCA devices both support a PCI-X interface; the switch IC does not require a bridge to PCI-X, Intel said. Brace said Intel's host solution will support multiple full-duplex 2.5-Gbit/s connections, with the serializer-deserializer kept off-chip, at least in the first-generation products.

Brace declined to say how many ports each device would support, saying that different feature sets will be required in the different application spaces.

Intel's chip samples will ship with software modules. "We don't expect our customers to rewrite their operating systems or their BIOS," said Brace. "We have a complete strategy for Infiniband, which means the chips and software modules for the host, switch and targets."

Outside the box

Infiniband servers will "have their interconnect outside of the box," making it easier to add servers than it is now, said Brace. This is a critical issue for many companies that outsource their data centers to firms that provide space, an uninterruptible power supply, access to bandwidth and physical security.

"Companies will pay anywhere from $100 to $200 per square foot per month for these services," said Kevin Deierling, vice president of marketing for Mellanox. "So the success of these companies is determined by how many users can be supported per cubic foot in a facility space," making the compression of server size — by linking the thin 1U and 2U-size servers by means of Infiniband switches — a vital practice.

Interoperability is a key concern with any new interconnect scheme, particularly given the industry's difficult experiences with Fibre Channel. Now established as an interconnect for multiple storage devices, Fibre Channel at first was so loosely defined that spec-compliant products from multiple vendors often could not interoperate.

"Infiniband has to take the lessons from the Fibre Channel space to heart," said Chris Pettey, chief technology officer at Banderacom Inc. (Austin). The detailed, 1,800-page Infiniband spec is designed to alleviate interoperability challenges.

Moreover, Brace said that Intel Capital is investing in many companies that will help develop "the Infiniband ecosystem." One focus of those investments is on the software tools needed for interoperability.

"There are significant efforts under way to ensure interoperability, including acceptance tests, plugfests and other methods that are still somewhat up in the air. These are being coordinated primarily by the Infiniband Trade Association," Brace said.

Indeed, interoperability will be foremost on the minds of many people working on Infiniband solutions, said Bob Pearson, vice president of business development at Vieo (Latin for "to weave"). "Most of the people who were involved with developing the Infiniband specification are the same people who got burned on Fibre Channel," he said.

"There are two ways to look at interoperability issues. One question is, 'Do you follow the specification?' Another is, 'Do you work with someone else's hardware?' Both are critically important," said Banderacom's Pettey. "If it states in the specification that a packet format looks like this, with a certain byte range in the fields, the spec may not call out every single field range. So your system may not be able to interoperate without testing."

Test development

Banderacom expects to ship its silicon, aimed primarily at target systems, later this year and is working with Dell Computer, Crossroads, Intel and others to develop compatibility testing methods, he said.

Beyond interoperability questions, Bert McComas, principal analyst at Inquest Market Research (Phoenix), has expressed doubts that Infiniband will be able to easily push aside PCI-X, a half-duplex, shared-bus architecture now finding its way into servers. Though PCI-X is not a full-duplex interconnect, McComas said many real-world applications are either a read or write mode and thus are well-served by PCI-X. Moreover, PCI-X builds on the huge PCI infrastructure, he said.

"The first pieces of Infiniband may also show up in late 2001, but because it is an external interface, it will be of little use until all of its infrastructure arrives as well," McComas said in a recent report on Infiniband. Needed, he said, will be server chip sets, new servers and peripherals, "new external switches, new cabling and, finally, a massive software development that will be required in order to turn Infiniband on. This is no cakewalk. It is difficult to imagine how all of this could be meaningfully deployed even in 2002."

The interconnect relies on "a complex software command protocol that must be supported by the OS, the drivers, the peripheral interface hardware and even the server application software in some cases," McComas said. "First-generation systems will decode this command protocol using processors and a software stack that must be added to Infiniband devices. Later, response time will be improved through full hardware acceleration requiring many millions of gates of silicon and lots of debug."

That is why the Agilent Technologies systems could become a key part of the Infiniband puzzle. Agilent's protocol analyzer provides debug and verification tools for engineers doing Infiniband component, module or system design and software development. Developed in conjunction with Computer Access Technology Corp., the package includes an analyzer and traffic generator. It is priced at $45,000 and up.

The company's 81600 Infiniium digital communications analyzer oscilloscope, meanwhile, is targeted at digital designers verifying the signal integrity of printed-circuit boards, cables and connectors incorporating Infiniband technology. Plug-ins are available that provide 20- to 50-GHz bandwidth and single-ended and differential time-domain reflectometer measurements. The oscilloscope is $16,500, while the differential TDR module will be priced at $13,500.

Agilent's 16700 logic-analysis probe connects to an x1 Infiniband cable for tracing Infiniband traffic. Targeted at board and chip set designers and system-validation teams, the probe helps define logic-analyzer triggers in terms of the Infiniband packet protocol. It allows users to view time-correlated measurement results as decoded Infiniband packets.