Gadzoox Flicks on Arbitrated Loop Switch

Early builders of storage area networks (SANs) using Fibre Channel technology will get a new option this week when a modular Arbitrated Loop switch from Gadzoox Networks Inc. makes its debut.

Early builders of storage area networks (SANs) using Fibre Channel technology will get a new option this week when a modular Arbitrated Loop switch from Gadzoox Networks Inc. (www.gadzoox.com) makes its debut.

The market entry of the high-density switch, called Capellix, repositions the Arbitrated Loop protocol as a more competitive -- and less expensive -- alternative to Fibre Channel Fabric switched environments. Gadzoox plans to drive switch-per-port pricing down while retaining the conveniences offered by Fibre Channel Arbitrated Loop hubs. Gadzoox will demonstrate the switch next week at Networld + Interop in Las Vegas.

Capellix is built in a modular fashion with three plug-in slots and offers high-availability features, including redundant cooling and power supplies. The backplane supporting the plug-in modules provides 28 GB of bandwidth, which ensures non-blocking 1 Gbps point-to-point performance, even in a fully populated switch with 24 connected ports.

Three different plug-in modules are available to expand the chassis, including a eight-port DB-9 copper wiring adapter, an eight-port short wave, and a six-port gigabit interface connector (GBIC) adapter. The switch is managed through an out-of-band network connection using Gadzoox's Ventana SAN Manager package.

Most Fibre Channel switches support Fabric switching, which is a non-blocking point-to-point connectivity protocol used for high-end applications, particularly processor-to-processor connections. Fabric switching is used in some storage configurations, but critics contend Fabric switches and other Fabric-connected components offer poor interoperability in multivendor configurations.

While Fabric switching is considered to be the high-end environment for many Fibre Channel components, much of the market growth has been around storage use and the Arbitrated Loop protocol, which offers a lower-overhead, easier-to-implement solution. Most Fibre Channel storage subsystems offer Arbitrated Loop connectivity.

The availability of Arbitrated Loop switching is expected to put pricing pressure on Fabric switch vendors such as Brocade Communications Systems Inc. (www.brocade.com), which sells a line of Fabric switches under the SilkWorm name. Some Fabric switches support Arbitrated Loop switching by layering that protocol over the Fabric protocol. Gadzoox spokesmen contend that design requires carrying higher-cost Fabric technology as overhead. Capellix is priced at just under $10,000 for an 8-port switch, and can offer per-port prices of $625 for a fully populated switch. By comparison, Fabric switches often cost $1,200-$1,500 per port.

Long-term plans call for the Capellix product to add Fabric switching capabilities, but according to Kurt Chan, vice president of engineering at Gadzoox, the dual-protocol switching won't be available soon. For now, Gadzoox does offers another product, the Denali switch, which can perform protocol-to-protocol conversions.

Capellix is designed to expand the configuration options Arbitrated Loop can use and to replace an existing hub or managed hub without any cable routing modifications. "This has been designed to look just like a hub," Chan says. Beyond the look, he expects most applications will be for hub-like environments. "The biggest application for switches today [is] emulating hubs, doing zoning," Chan adds.

International Data Corp. (IDC, www.idc.com) analysts Aaron Schatz and Robert Gray note in a written IDC Flash that, "The storage switch can replace a hub in a lower-end SAN, providing an accelerated performance similar to a Fibre backbone switch at a lower cost than moving to a conventional switch." They said the benefits include not having to upgrade operating systems, firmware or other hardware components.