Long-distance fixes for Fibre Channel

A growing number of government agencies are looking to stretch the reach of their Fibre Channel-based storage-area networks (SANs). "After [Sept. 11, 2001], many government agencies started to look for ways to extend their data storage backup and recovery systems to longer distances," said Steve Duplessie, a senior analyst with the Enterprise Storage Group.

This is a difficult proposition with traditional Fibre Channel connections, because their maximum length is 10 kilometers. Consequently, suppliers have focused on using the general-purpose TCP/IP networks that most organizations run to enable Fibre Channel transmissions to travel greater distances. So far, two options have emerged.

One is Fibre Channel over IP, which is a protocol for "tunneling" Fibre Channel through an IP network. This approach is used for point-to-point connections between SAN islands because it does not take advantage of routing or other IP management features. It is supported by many vendors, including Broadcom Corp., Brocade Communications Systems Inc., Cisco Systems Inc., Hitachi Data Systems and McData Corp.

"We're optimistic about [Fibre Channel over IP] acceptance and think it offers our customers the best option for extending their SANs via TCP/IP," said Bill Erdman, director of marketing at Cisco.

The other option is the Internet Fibre Channel Protocol, which wraps Fibre Channel data in IP packets. It also maps IP addresses to individual Fibre Channel devices, allowing for finer control when managing distributed SANs.