The updated Infiniband roadmap comes at a time when Ethernet proponents are preparing for a leap from 10 to 100 Gbits/s. A 100G Ethernet standard is well along in development and some vendors plan to demonstrate a pre-standard version of the technology at NXTcomm in Las Vegas.

This year the primary supplier of Infiniband chips, Mellanox Technologies, began shipping quad data rate switches that run at a 10 Gbit/s serial rate. The QDR chips can support maximum throughput of up to 120 Gbits/s over a 12-lane connection.

The Infiniband Trade Association is already discussing the feasibility of a 16x or so-called hexadecimal data rate that could deliver 40 Gbit/s serial channels in about six years, said Thad Omura, vice president of product marketing at Mellanox. Meanwhile Infiniband backers are also working on enhancements to quality-of-service and smaller 12-lane connectors.

Infiniband has long provided more bandwidth and lower latency than Ethernet, with application-to-application latency rates currently at about one microsecond. The new standard will not address latency which is handled as a product implementation issue.

"The latency figures for Infiniband are more application specific but we expect there will be advances in low latency," said Omura.

The Infiniband community has doubled data rates in each of its previous generations. Engineers determined the 20 Gbit/s rate would be well matched for cards based on the upcoming PCI Express version 3.0 standard now in the works. They also believe underlying serdes, board layout, cabling and connector technologies will be available to support the 20 Gbit/s rates by 2011.

Infiniband will retain its position as the highest performance technology, but Ethernet is on a track to grow the share of data center traffic it carries, according to Mike Krause, an interconnect specialist in Hewlett-Packard's PC server group.

"Moving beyond 10 GTransfer/s signaling is hard and expensive at this time [so] whether people have the fortitude to go faster is a good question and one without a formal answer by the industry at large," said Krause.

Infiniband has seen growth because it is the leading interconnect for computer clusters which are being used for a growing list of applications. However, with the rise of Fibre Channel over Ethernet and Infiniband over Ethernet "it is clear the industry volume is pushing for Ethernet to remain the volume interconnect and dominate over time," he said.