IP storage on the way

The much-anticipated convergence of storage and network traffic is moving closer to reality through a pair of competing standards initiatives from the biggest names in network infrastructure and a handful of start-ups.

Earlier this month Lucent Technologies Inc. and Gadzoox Networks Inc. announced a proposed specification for tunneling Fibre Channel data through IP networks. The traffic would first be encapsulated in IP by newly developed Fibre Channel to gigabit Ethernet routers. The companies have submitted a specification to the Internet Engineering Task Force (IETF) that allows clusters of SANs to be bridged remotely by LANs, WANs or metropolitan-area networks (MAN). The proposal, which is in an IETF working group, could emerge as a standard late this year, according to Gadzoox.

IBM Corp., Cisco Systems Inc. and storage management start-up SANgate say that tunneling Fibre Channel in IP packets alone, while a good way to bridge SANs over long distances via any IP-based network, is only an intermediate step in converging SANs with LANs.

Instead, these companies are promoting the use of SCSI over native TCP/IP, using TCP for the flow control and security they claim Fibre Channel shouldn’t have to provide. The trio has submitted a draft to the IETF that has not yet been codified into working group status. Their plans to implement SCSI over TCP are more long range and are not expected to result in any products for at least nine months, says Clodoaldo Barrera, strategy director for storage systems development at IBM.

“The big distinction is not Fibre Channel or SCSI,” Barrera says, “it is whether [data] should be sent over TCP/IP or IP alone.” According to Barrera, TCP already provides flow control and security, and it doesn’t make sense to duplicate these functions with Fibre Channel.

In February, James Richardson, the senior vice-president in Cisco’s Enterprise line of business, was asked if Cisco would be a player in the storage area network market.

His response was, “Right now it’s a Layer 2 game, and we’ve never done really well at a Layer 2 game. If the market evolves to where there are application requirements for TCP, then I think you’ll see our involvement.”

He did not let on that Cisco was already involved. A month beforehand, Andy Bechtolsheim, vice-president of Cisco’s gigabit switching group, was evangelizing Cisco’s interest in the market. That month, Cisco jointly submitted with IBM and SANgate, an Israeli company, a proposal to the IETF for running SCSI over TCP. And a Cisco executive joined the board of Nishan, a SAN start-up in Santa Clara, Calif.

“We’ve started to see some interest, rather than deployment plans, for interconnecting SANs across the WAN,” says Duncan Potter, a product line manager in Cisco’s workgroup business unit. “We’re a natural because of our involvement in IP.” The current requirement is for SAN interconnection over a MAN, Potter says. But users are looking for a MAN infrastructure with less latency than Fibre Channel, the current SAN technology standard, he says.

Potter became tight-lipped when asked which technologies Cisco recommends for replacing Fibre Channel, only saying the company will be making “broader SAN involvement announcements over the next 12 months.” But Cisco’s Richardson said in February that he believed 10Gbps Ethernet was a natural for that.

Last month Cisco announced the Metro 1500, an enterprise wavelength division multiplexer that can be used to provide an inexpensive MAN connection for SANs. But a Cisco spokeswoman says the Metro 1500, which is private-labeled from Adva, is not a strategic SAN offering.

Meanwhile, Bechtolsheim in January made a presentation on “The IP SAN” at the Server I/O conference. Bechtolsheim talked about the possibility of using the IP infrastructure and Gigabit Ethernet or 10Gbps Ethernet to carry SAN data.

Gadzoox isn’t slowed by the standardization process, and, at press time, was expected to show off a Fibre Channel-to-Gigabit Ethernet router at NetWorld+Interop 2000 earlier this month in Las Vegas. This router, code named Black Widow, will allow SANs to connect to each other via a local gigabit Ethernet network or an IP router from the likes of Lucent, Cisco or IBM.