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.
Lucent Technologies and Gadzoox Networks next week are expected to announce 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, Cisco Systems 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.
"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 10G bit/sec Ethernet was a natural for that.
Cisco today is expected to announce 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 10G bit/ sec Ethernet to carry SAN data.
Gadzoox isn't slowed by the standardization process, and is expected to show off a Fibre Channel-to-Gigabit Ethernet router at NetWorld+Interop 2000 next week 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.
Users have been reluctant to deploy SANs in major projects because of the newness of the Fibre Channel technology. They are concerned about its interoperability with other devices and the traditional network infrastructure.
"If I had some disparate locations, [Fibre Channel over IP] would be very important to me," says Steve Lopez, architect of enterprise infrastructure and networking for the National Board of Medical Examiners in Philadelphia. "I have some remote sites I do a lot of data collection for. If I could set a device out there that collects data from a TCP/IP-based server and send it as if it were a remote [Fibre Channel] disk, that would be very handy."
Storage vendor Crossroads Systems also plans to introduce Fibre Channel to Gigabit Ethernet or ATM routers later this year. SanCastle, a start-up in San Jose, plans to ship a Fibre Channel-to-Gigabit Ethernet switch in the third quarter.
Computer Network Technology (CNT) previously led the move to SAN/WAN convergence with its ability to transport EMC Symmetrix Remote Data Facility data and other Fibre Channel data over IP using a proprietary technology, which sends blasts of data with only semiregular receipt acknowledgments. Finisar also has had Fibre Channel extenders that allow SAN data to be transported across long distances. The Gadzoox-Lucent specification is the first to use standard protocols for data transport. CNT will move to standard protocol use over the next 12 months, the company says.
In the short term, the IBM-Cisco proposal looks to join geographically separated storage directly to client workstations without intervention of a server or host computer. It would do so by creating a single network adapter that is placed in the workstation, which would access both the IP network and storage on the network. Devices such as cell phones or personal digital assistants would also be able to access network storage in this manner and store the information on compact, ultra-dense disk drives IBM is developing, IBM's Barrera says.
"In the longer run, you can imagine designs where you can create a completely seamless all-TCP/IP network, which consists of a lot of physical networks and all sorts of data," Barrera says. "Far term, companies are going to start making TCP hardware accelerators, and will start to make use of the security and other elements missing in Fibre Channel."
Users say any advance that brings storage data over the network infrastructure is better than what they have now.
"I could mix Fibre Channel and IP together and give data quality of service because my infrastructure already supports IP-based QoS," Lopez says.