Instead, Microsoft is betting on Gigabit Ethernet and Fibre Channel for blade server clustering and storage device connectivity within Windows .net Server. That approach relies on existing IT infrastructures and should help users contain costs, according to Microsoft.
Valerie See, group manager of Microsoft's Windows Hardware Evangelism division, said IT managers are "gravitating toward evolutionary technology that allows them to use existing technology [as opposed to] an expansion of capabilities or a wholesale replacement of an existing architecture".
Microsoft had planned to put native support for InfiniBand in Windows .net Server, which is due to ship by the end of the year. Instead, it became the second major IT vendor to back away from the technology, following a decision by Intel to stop developing InfiniBand controller chips.
Dell Computer had been working with Microsoft and start-up InfiniBand vendors to use the high-speed I/O interconnect as the backbone for its upcoming PowerEdge "brick" servers, which will enable modular configuration and reconfiguration of rack-mounted servers.
Jimmy Pike, director of server architecture and technology at Dell, said InfiniBand is still the leading technology "for the problem we're trying to solve: creating a high-bandwidth, low-latency interconnect".
"There are other software avenues besides Microsoft," he added.
Some $300m (£192m) has been invested in dozens of InfiniBand start-ups to date, according to IDC. Analysts said Microsoft's withdrawal was likely to hurt this emerging market.
"That's the No. 1 server platform on the planet, and when they back away, it has ramifications on the entire server community," said Steve Duplessie, an analyst at Enterprise Storage Group.
However, observers said Microsoft's move did not signal a general deterioration of support for the technology. Both Intel and Microsoft have said they will work with third-party vendors to integrate InfiniBand into their products.
But users wanting to employ InfiniBand as the backbone I/O technology for clusters of systems based on Windows .net Server, will now have to buy drivers from other vendors.