By Dave Simpson
JAY KIDD - Vice president of product marketing, Brocade
Last month, the leader in Fibre Channel switches and the leader in IP switching teamed up in a multi-phased technology development agreement that will enable IT shops to interconnect storage area networks (SANs) over IP-based metropolitan and wide area networks. The announcement came one month after Gadzoox Networks and Lucent Technologies announced a similar agreement to enable the transmission of Fibre Channel traffic over IP networks, such as Gigabit Ethernet (InfoStor, June, p. 1).
"Users want a way to interconnect their Fibre Channel SANs over long-haul networks, ideally using their existing TCP/IP infrastructure," says Jay Kidd, vice president of product marketing at Brocade. "And there is also great interest in connecting via DWDM [dense wavelength division multiplexing] in optical MANs [metropolitan area networks]."
Potential applications for remote SANs include disaster recovery, data replication, data backup, clustering, and digital content distribution.
In the first phase of the agreement, the two companies will jointly develop a Fibre Channel interface for Cisco's Catalyst 6000 switches, with Cisco licensing Fibre Channel technology from Brocade. Cisco will incorporate Fibre Channel E_Port technology in its IP switches. Cisco plans to deliver Catalyst switches with Fibre Channel ports in the first half of 2001.
In this scenario, a Fibre Channel switch connects to a Cisco switch using the E_Port. The Cisco switch encapsulates Fibre Channel in TCP/IP, and Fibre Channel is transported across the MAN/WAN using TCP/IP. The Fibre Channel traffic is de-encapsulated at the other end (see diagram).
Also in the first phase of the agreement, the two companies will certify interoperability between Brocade SilkWorm Fibre Channel switches and Cisco's DWDM products. DWDM would enable SAN-to-SAN connectivity over high-speed fiber-optic MANs.
Emphasizing the non-exclusivity of the deal, both companies say that any vendor's Fibre Channel switch that supports E_Port connectivity will work with the Fibre Channel-equipped Cisco switches. The ANSI T11 standards committee recently agreed on a routing protocol for E_Port interoperability, which should become possible by the end of the year.
Brocade-Cisco technology will enable companies to interconnect SANs over IP-based MANs and WANs.
"We plan to interoperate with other vendors' Fibre Channel switches," says Duncan Potter, Cisco's product line manager for IP switching and storage area networks. "The technology will work with any switch that supports E_Port connectivity," he says.
In goal, the Brocade-Cisco technology is similar to what is already available from Computer Network Technology. CNT's UltraNet Gateway family allows users to link Fibre Channel SANs over IP networks, which CNT refers to as "SAN over IP."
At the same time that vendors such as Brocade and Cisco, and Gadzoox and Lucent, are developing methods for running Fibre Channel traffic over IP networks, a number of vendors are working on methods to run SCSI over TCP/IP and/or IP. Examples include Nishan Systems, Adaptec, and IBM in partnership with Cisco (InfoStor, June, p. 1).
"As standards such as iSCSI [the joint IBM-Cisco proposal for SCSI over TCP/IP] get tested, we'll look at how to provide a migration path to those technologies," says Cisco's Potter. "The Cisco-Brocade technology is a TCP/IP-based transport system. We think that the longer-term solution will be based on something like iSCSI."
Brocade has a similar, yet subtly different, view. "For interconnection of SANs, it's beneficial to use existing IP networks, and that's why we're encapsulating Fibre Channel over TCP/IP," says Brocade's Kidd. "SCSI over TCP/IP may also be a good approach when Fibre Channel devices aren't at either end. But at this point, Fibre Channel is widely installed for storage area networking, and any alternative will have a pretty high bar to cross."