An emerging storage protocol, supported by industry heavyweights like IBM, Cisco and EMC, promises to make storage area networks available to small and medium-size businesses and in the process create a market that is forecast to be worth $5 billion over the next four years.Because they can use inexpensive Ethernet adapters and switches to transfer data, SANs built using the Internet Small Computer Systems Interface (iSCSI) could be cheaper and easier to manage than those based on the dominant SAN interconnect, Fibre Channel. But analysts warn that until smaller startup vendors prove that there really is a market for iSCSI, vendors like HP, IBM, and EMC will be reluctant to fully support it in their product line.When it was first proposed three years ago, the iSCSI protocol looked good on paper. It was based on a simple idea: Take the SCSI interface that most servers use to send block-level data to their hard drives, bolt it onto the ubiquitous TCP\/IP networking protocol, and suddenly you have a storage protocol that can run over Ethernet.Approved by the Internet Engineering Task Force in February, iSCSI arrived a few years behind Fibre Channel. And while Fibre Channel components are much more expensive than their iSCSI counterparts, and require special networking expertise, the Fibre Channel transport has one big advantage: there are products shipping that use it. Companies like Sun, EMC, and HP have been selling Fibre Channel storage devices for years and it is firmly entrenched in the enterprise.Some of those same vendors have dabbled with iSCSI over the last few years. IBM was first out of the gate, releasing its TotalStorage IP Storage 200i array in June 2001, and HP released an iSCSI router called the StorageWorks SR2122 router this February. But the bulk of iSCSI products have come from smaller vendors like Network Appliance\u00a0and Sanrad, as well as Cisco, which has released a number of products designed to connect iSCSI to Fibre Channel and SCSI arrays.Though the big vendors remain tight-lipped about when, if ever, they plan to integrate iSCSI into their existing storage product lines, observers believe that this will happen only after smaller start-up companies have proved that there is a viable market for iSCSI devices."The start-ups are the leaders because the startups are the ones that are out there today," said Larry Boucher, CEO of Alacratech, speaking at IDC's StorageVIsion conference in San Jose last week. "They are the ones who are going to pull the big guys into this business," he added.The market for iSCSI arrays was a miniscule $12 million last year, according to IDC, but the research firm predicts that it will rapidly grow to the point where the HPs and EMCs of the world will be forced to take notice, hitting $4.9 billion by 2007.iSCSI's growth is expected to far surpass that of Fibre Channel over the next four years, but its total market size is not, and analysts say they expect the two technologies to complement, rather than compete with each other. IDC predicts that Fibre Channel will remain entrenched at the high end, with its broader vendor support and superior speed, while iSCSI will make inroads in small and medium-size businesses because of its lower price and ease of use.Gartner analyst James Opfer agreed. "(iSCSI is) not going to displace Fibre Channel in the current state of affairs," he said. With Fibre Channel running at a data rate of 1.6G\u00a0bit\/sec compared to iSCSI's 1G bit\/sec, it has enough of a performance advantage to remain viable, he said.But for those who are happy with iSCSI's 1G bit\/sec transfer rate, and who may not have the money to purchase the more expensive Fibre Channel network cards and switches, iSCSI can be compelling.The University of Alabama is a typical early adopter. When Sterling Griffin, the University's Department of Pathology IT Manager compared the price of Fibre Channel components to iSCSI, he soon realized that Fibre Channel would be prohibitively expensive. "I looked at a couple of components and just the cost of the base switches and bridges was out of our budget."Instead of buying $1,000 Fibre Chanel networking cards and $7,000 switches, Griffin said that he bought $175 Ethernet cards from Intel, and a $1,000 Linksys Gigabit switch. These components then connect to an iSCSI-to-SCSI V Switch 3000 bridge from Sanrad, which lists for $15,000.Another major benefit was the fact that it took so little network training to get iSCSI up and running, said Griffin. "From a technical standpoint, for me to teach my lead technician how to use it and how to configure it was very simple," he said.Dan Hague, who is using iSCSI to connect arrays on a video on demand network at the University of Michigan, agreed. "If I go to Fibre Channel," he said, "I've got to build a whole new knowledge base. So really it allows me to use what I have to have anyway... I don't have to have a Fibre Channel expert (on staff)," he said.Because of the huge amount of traffic that moving your storage systems to your TCP\/IP network can create, iSCSI creates, Hague warns that the toll on your network can be overwhelming. "If you don't have good network people, don't do it," Hague said. "This will reveal problems in your network."Today, the iSCSI market is dominated by switching devices, like Sanrad's, that convert iSCSI traffic to Fibre Channel or SCSI, but iSCSI storage systems are beginning to emerge.Network Appliance\u00a0 has been shipping two arrays -- the NetApp F800 and FAS900 -- since February, and next month start-up Intransa will begin shipping what it bills as the first highly scalable iSCSI array, capable of up to 10 terabytes of storage.Although IBM was among the first to ship an iSCSI product, it now portrays its 200i product as a "primer for the market," rather than the basis of its iSCSI product line, according to IBM Director of Storage Strategies Clodoaldo Barrera. "What we wanted was to have a platform that people could play around with," he said "But we did not think then, nor do we think now, that the 200i is the final optimized... product," he said.IBM expects to introduce more iSCSI products by early 2004, Barrera said. Low and midrange products will probably include "native attachment of iSCSI devices," he said, but for the enterprise, where users will want to protect their investment in Fibre Channel, "you can expect to see these multiprotocol switches to the Fibre Channel SAN... supporting at a distance, perhaps, an iSCSI deployment," he said.EMC says that it will support iSCSI in its Clariion and Symmetrix product lines, and HP says that it could ship iSCSI arrays as early as 2004.One of the big vendors that is particularly cool on iSCSI is Sun. While Sun Storage Chief Technology Officer Balint Fleischer says that iSCSI does "hold promise" in the small workgroup space, he says that the "the reality is iSCSI is not a mature technology, and we have to see how it matures."While Sun was an early investor in iSCSI technology, "the more time progressed, the more skeptical we became about how fast and how soon iSCSI is going to be adopted," Fleischer said.IDC predicts that iSCSI will first catch on as a direct-attached storage technology, with 85% of iSCSI sales being direct-attach in 2004. But after that, about the time that the large vendors are expected to get involved, SAN deployments will begin to dominate the iSCSI market, making up 65% of total sales by 2007. But as popular as IDC expects iSCSI to become, it will by no means replace Fibre Channel. IDC predicts that Fibre Channel SAN sales will remain ahead of iSCSI for the foreseeable future, growing to more than $6 billion by 2007.The research firm, owned by International Data Group Inc., the parent company of IDG News Service and Network World, estimates that the lion's share of growth in the SAN market will come from inexpensive iSCSI arrays targeted at small to medium-size businesses."There will need to be targets in the $10,000 price range and below," said IDC analyst Robert Gray. "They're not the people who are spending $30,000 or $100,000 on storage."