By Dave Simpson
Cisco recently rounded out its Fibre Channel switch line with 20-port and 40-port MDS 9100 series fabric switches. Previously, the MDS 9216 was the company's low-end offering. However, the 9216 can be scaled from 16 to 32 or 48 ports and can handle multiple protocols and add-in line cards. In contrast, the 20-port 9120 and 40-port 9140 are fixed-configuration devices that support only Fibre Channel (1Gbps or 2Gbps).
The switches will compete primarily with Brocade's SilkWorm 3800 and McData's Sphereon 4500 fabric switches. Pricing will be determined by Cisco's OEMs. Hewlett-Packard, IBM, and EMC were expected to begin shipping the 9100 series switches this month.
Figure 1: Fabric-based LUN zoning can be used with, or in place of, array-based LUN zoning.
According to Tom Harrington, product manager for the MDS 9000 family, Cisco plans to differentiate its switches from competitors' primarily in the richness of the feature set. Almost all of the features available on Cisco's higher-end switches (such as its Fabric Manager software and support for
Virtual SANs, or VSANs) are included in the 9100 series, with the exception of multi-protocol support and services-oriented features available on add-in cards, such as IP storage services and support for virtualization and fabric-based applications.
The high-density (1U) 9100 series is targeted primarily at entry-level storage area network (SANs), "edge-to-core" connectivity into larger SANs, and at companies that are beginning to migrate from direct-attached storage configurations.
Cisco also announced the 1.2 version of its SAN-OS software, which works across the company's entire line of switches—including the 9100 series. The software is included at no additional cost. A number of the new features are security-related, including
- Fabric-based LUN zoning (see Figure 1 on p. 10). Previously, the operating software supported only WWN and port zoning. Fabric-based LUN zoning can be used in place of, or in conjunction with, LUN zoning from disk array vendors or third-party software vendors and can be particularly advantageous in heterogeneous array environments.
- Support for read-only zones (see Figure 2), which enables a volume to be shared across different servers. Zoning is based on SCSI I/O type (read-only or read/write).
- Port-level security, which allows administrators to control which port(s) a server or storage device can connect to. Port-level security can also prevent SAN misconfigurations.
Another addition in SAN-OS 1.2 is support for "legacy switch interoperability mode," which allows MDS switches to interoperate with other vendors' switches without putting those devices in interoperability mode (which can require re-setting switches and fabrics). The qualification matrix for this feature will be determined by Cisco's OEMs (which the company now refers to as original storage manufacturers, or OSMs).
Figure 2: Read-only zones enable a volume to be shared across different application servers.
Other features introduced in SAN-OS 1.2 include VSAN-based roles (an access-control mechanism), and remote capability for Cisco's Switch Port Analyzer, called RSPAN.
The next release of SAN-OS, due by year-end, will have support for FICON. Cisco has licensed FICON control unit port (CUP) specifications from IBM.