By Dave Simpson
Following a long-standing trend in the IP/Ethernet switch market, QLogic last month began shipping the industry's first stackable Fibre Channel switches. Stackable IP/Ethernet switches have been available for about a decade from vendors such as Cisco, Nortel, and 3Com and currently account for the majority of Ethernet switch port shipments.
In addition to citing potential scalability, space-, and cable-saving advantages, QLogic officials note that stackable switches can decrease the number of inter-switch links (ISLs) required as users scale port counts. For example, in a storage area network (SAN) environment with 64 servers and/or storage devices, a stackable configuration of four switches requires eight 10Gbps Fibre Channel ports for ISLs, but does not require any 2Gbps user ports for ISLs. In contrast, the same SAN environment with modular switches in a mesh fabric would require six switches and 32 2Gbps user ports for ISLs (see diagram).
QLogic's use of 10Gbps Fibre Channel ports for ISLs in its SANbox 5200 switches is another industry first, according to analysts, although other SAN switch vendors are expected to introduce support for 10Gbps Fibre Channel later this year. (Cisco, for example, plans to deliver 10Gbps Fibre Channel within the next three months.) Each SANbox 5200 comes with four 10Gbps connections for ISLs. The 10Gbps ports can also be used to link the switch to storage devices and servers.
QLogic's SANbox 5200 comes in a 1U form factor with 16 physical Fibre Channel ports (1Gbps or 2Gbps), although users can implement it in 8-port increments. For end users looking for low-cost SANs, the price of the 5200 may be the real eye-opener. In fact, an 8-port entry-level configuration is priced at $5,795 (MSRP), or $724 per port.
Users can scale SANbox 5200s up to 64 ports by stacking four switches, without losing any ports to ISL connections. Ports can be added in 4-, 8-, 12-, or 16-port increments.
The switch ships with QLogic's wizard-based SANsurfer Management Suite software for configuration and management. Other features include non-disruptive code load and activation (NDCLA).
The SANbox 5200 is available from QLogic's distributors, which include Arrow, Bell Microproducts, Info-X, MOCA, Promark Technology, Tech Data, and TidalWire.
Not all switch vendors think that stackable switches and 10Gbps Fibre Channel connections are the way to go—at least not for small and medium-sized businesses (SMBs). "Stackability is interesting, but one of its main advantages is simplified management, which can also be accomplished with software that views all the switches in a fabric," says Jay Kidd, CTO of infrastructure systems at Brocade. "We believe that modular directors and low-cost, fixed-size switches will result in the best overall cost and ease of management for the SMB market."
Regarding 10Gbps Fibre Channel, Kidd contends that "the most compelling use for 10Gbps speeds will be for linking director switches together.
"We don't see the SMB market as the entry point for the more expensive 10Gbps technology."
Stackable switches reduce the number of user ports required for inter-switch links (ISLs).