If you are a reseller specializing in storage, you've probably bumped into customers who—quite literally—want to get more mileage out of their storage area networks.

Indeed, customers would like to interconnect SAN islands, but Fibre Channel's range is limited to about six miles. That's a problem for organizations that want to mirror their data off-site for disaster recovery purposes or remote backup. A number of technology strategies and vendor offerings aim to get around this barrier.

Cisco Systems Inc. is the latest vendor to jump into this SAN-extension game. The company Monday expanded its MDS 9000 line of storage switches and directors, adding hardware and software products that the company says will facilitate the flow of SAN traffic beyond the data center.

And while Cisco is a relative newcomer to storage, some integrators believe the company's networking heritage lets it challenge the more established players. Cisco's new offerings are pushing competitors to keep pace when it comes to "moving packets over distances in the storage area networking world," said Marc Duvoisin, national director of enterprise servers and storage at Dimension Data, an IT solutions provider.

Cisco's MDS 9216i fabric switch and MDS 9000 Multiprotocol Services Module employ 14 Fibre Channel ports and two Gigabit Ethernet ports. These can be programmed to support FCIP (Fibre Channel over IP) or iSCSI, according to the company.

Cisco also unveiled SAN extension features in SAN-OS 2.0, the latest version of the MDS 9000 operating system. Rajeev Bhardwaj, senior product manager for the Cisco MDS 9000, says the product launch dovetails with customers' SAN plans, noting that many customers now seek to extend SANs for business continuity applications. A Cisco survey last year identified SAN extension for business continuity as a top priority.

Click here to read about how iSCSI systems are giving IT managers storage flexibility.

In general terms, customers have become increasingly interested in bridging SAN islands. Duvoisin said both large enterprises and small-to-midsize businesses "have isolated SAN fabrics today that are relatively small in size." Sometimes SANs are physically close enough to be connected via Inter-Switch Link. If not, Duvoisin says, organizations want to find a cost-effective means for interconnecting SANs.

Cisco's SAN extension rollout provides cost-saving features, according to the company. For one, Cisco offers hardware-based FCIP compression, which can help companies utilize less expensive WAN circuits. Through compression, a customer may be able to use a DS-3 circuit at $7,000 per month compared with an OC-3 circuit at $24,000 per month, according to Bhardwaj.

On the extension side, Cisco is extending the range of Fibre Channel over DWDM and Sonet. The company says its new hardware offers up to 3,500 buffer credits per Fibre Channel port. Bhardwaj says the rule of thumb is 2 buffer credits per kilometer, which means the product can span distances of up to 1,750 kilometers (1085 miles).

Distance isn't typically a problem with IP, but security is. Cisco provides hardware-based IPSec encryption to boost the privacy of extended SAN applications.

Duvoisin, meanwhile, believes Cisco will stick to the channel in the SAN market as it has in networking. He notes that Cisco's history isn't in replication, backup and recovery. That's where storage-specialty partners come in.

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