) is taking steps to make iSCSI a reality.NetConvergence designed chips for host bus adapters (HBAs) to convert SCSIcommands into iSCSI commands. “The SANlandscape has changed in the past few months,” says Simon Fok, president andCEO of NetConvergence. “Fibre Channel is going to hit a brick wall.” Fokbelieves the SAN user base will remain limited as long as SANs continue to bebased on the Fibre Channel protocol.
SteveDuplessie, senior analyst at The Enterprise Storage Group Inc. (www.enterprisestoragegroup.com), is enthusiastic about iSCSI. “I love it,”he says. “ISCSI is going to win.” Duplessie agrees with Fok that the primaryattraction of iSCSI is the ability to use TCP/IP equipment. “In a perfectworld, we’d only have one network,” he says. “A Fibre Channel network issomething new.” Duplessie believes Fibre Channel scares away many users,particularly Windows NT/2000 users, because it requires specialized hardware,infrastructure, and support. ISCSI offers an attractive alternative todedicated hardware -- and significant risks -- by allowing users to adoptinfrastructure that can be repurposed for standard TCP/IP.
Fok says itis over simplistic to say iSCSI encapsulates SCSI commands and data insideTCP/IP packets. He explains that the SCSI data stream is abstracted across astream of packets. Because the iSCSI protocol has all of the functionality ofSCSI, many of the features expected from Fibre Channel, such as serverlessbackup, can be implemented in iSCSI. In addition, block-to-block transfers canbe performed across large geographic distances allowing exact duplication ofstorage systems between data centers.
Untilrecently, TCP/IP networks were not considered suitable for pure storageapplications because of performance issues. “It’s not true any more that[TCP/IP] is not efficient,” Fok says.
Fok expectsiSCSI will be implemented alongside Gigabit Ethernet technology, particularlyin local SANs. Like iSCSI, Gigabit Ethernet has vendors such as Giganet Inc. (www.giganet.com) designing special chips that allow theprotocol work to be done on HBA silicon rather than in the CPU.
In additionto the oft-cited interoperability issues and the need for specialized hardware,Fibre Channel is also hampered by distance limitations -- because of latencyissues, standard Fibre Channel connections can currently stretch only 20kilometers. Fibre Channel chased out of the low-end market by the cost ofinstalling all new equipment and specialized staff. Then again, it has limiteduses in the high end where long-distance replication is essential to anInternet infrastructure.
Foksuggests that the iSCSI protocol may be a good solution for both ends of theuser spectrum: Users with fewer resources to draw on can retain TCP/IPinfrastructure devices while using a storage protocol, and users withlong-ranging storage systems can implement iSCSI to either connect FibreChannel-based data islands, or implement a Gigabit Ethernet SAN locally. NetConvergenceplans to market its chips to HBA manufacturers, integrating the iSCSIfunctionality into the network card. This allows iSCSI instructions to beprocessed in silicon, rather than in the CPU, improving performance. Fokforesees that HBAs used in iSCSI/Gigabit Ethernet implementations will containchips for both protocols.
LikeGigabit Ethernet, iSCSI requires software to be iSCSI aware -- able to takeadvantage of the chips. Fok says NetConvergence is fostering relationships withmajor storage management vendors to ensure that their software is iSCSI aware.
Fok alsocites IBM Corp. (www.ibm.com) and EMC Corp. (www.emc.com) as strong supporters of the iSCSIstandard. Although these vendors sell Fibre Channel products, they areinterested in any SAN technology their customers will want to buy.
Fok saysCisco Systems Inc.’s (www.cisco.com) purchase of NuSpeed networks validates hisnotion that storage networking will converge with traditional networking, inpart because the network infrastructure market will eventually stabilize,giving Cisco and others the need to expand into new arenas. NuSpeed createsstorage networking hardware. “You’re going to see Cisco put out some NuSpeedstuff with iSCSI,” Duplessie says.AlthoughNetConvergence expects to sell its chips to other vendors, the company hasreleased a product for users branded with the NetConvergence name. The MatrixEnterprise storage gateway connects storage devices with legacy SCSI cabling toGigabit Ethernet networks.
Although afull, end-to-end iSCSI SAN is months away, users can begin a limited iSCSIimplementation today. Duplessie expects iSCSI to hit the market in full forcewithin 18 to 24 months.