NEC's ExpEther extends PCI Express over Ethernet

NEC is developing a system that can extend the conventional PCI Express interface found in most PCs and servers over standard Ethernet to distances of 2 kilometers or more.

ExpEther, as the company has named the system, was unveiled on Tuesday at an NEC exhibition in Tokyo and demonstrated running on a PC that was connected to peripherals over the technology.

It works by placing ExpEther adapters, which in the prototype system look like regular PCI cards, at the end of each connection, said Atsushi Iwata, a senior manager at NEC's system platforms research laboratory.

A single adapter sits in the PC and handles the interface between the PCI Express bus and Ethernet network. At the far end of each network connection sits another ExpEther adapter and a conventional PCI Express adapter for the peripheral to be connected.

For example, a hard-disk drive was connected to a conventional Serial ATA card and a mouse and keyboard to a USB card. The ExpEther cards alongside each of the interface boards handled the conversion to Ethernet for the journey back to the PC.

While the arrangement makes for a lot of adapters and cards it has the advantage of allowing use of a PCI Express adapter and conventional network routers and switches.

The system can be easily visualized as a way of connecting any PC peripheral over longer distances than is possible now. Whereas a typical monitor or USB connection might start having problems once a cable exceeds a few meters this system works to at least 2 kilometers, Iwata said. He expects it will probably work to distances of several tens of kilometers although those lengths haven't been tested, he said.

Applications for the technology include blade server systems. Such systems typically have a common PCI bus that connects the servers and Ethernet to link with other cabinets and systems. Using this technology everything could run over Ethernet and potentially servers in several cabinets could link through a PCI bus.

NEC is also testing the technology with a broadcaster, which needs to be able to inject and store vast amounts of video while simultaneously having it immediately available for editing, said Iwata. It could also be used in the home to connect a house full of gadgets and appliances to a single home server.

The technology is still undergoing testing but NEC plans to open it to other companies. Later Wednesday, the company is scheduled to announce an ExpEther consortium consisting of around 20 companies that are initially supporting the technology.

The IDG News Service is a Network World affiliate.