AoE is a low overhead, non-routable storage protocol developed by Coraid.

http://www.coraid.com/

Coraid has a full line of storage products for SAN and virtualization projects.

Starwind also offers products and services with AoE support.

http://www.starwindsoftware.com/

http://en.wikipedia.org/wiki/ATA_over_Ethernet

The AoE protocol is open source and is widely included in various Linux distributions.

There is Windows driver support as well:

• http://winaoe.org/
• http://www.starwindsoftware.com/aoe-ataoverethernet-initiator

http://www.howtoforge.com/low-cost-san

http://www.linuxjournal.com/article/10780