Cisco extends SANs

By Dave Simpson

In what company officials billed as its most significant storage announcement of the year, Cisco recently released a number of products and enhancements in the MDS 9000 line of switches and software, most of which were related primarily to improving SAN extension.

On the switch front, Cisco shipped the MDS 9216i fabric switch and the MDS 9000 Multi-protocol Services (MPS) Module, both of which have 14 Fibre Channel ports and two Gigabit Ethernet IP ports that can handle either the iSCSI or FCIP protocols. Although the 9216i is a stand-alone switch and the MPS module is a line card that can be plugged into MDS 9500 or 9200 series switches, the two are functionally identical (see "at a glance" for product details).

Cisco also released the 2.0 version of its SAN-OS software. According to analysts, key features include the following:

  • FCIP tape acceleration. According to Rajeev Bhardwaj, Cisco's senior product manager for the MDS 9000, this feature can provide up to a 30x throughput improvement in remote backups, although actual performance depends on transmission distance, the type of tape drive, and other factors. In addition to the throughput improvement, tape acceleration enables longer transmission distances and the ability to cut costs by using less expensive WAN technologies. FCIP tape acceleration is implemented in SAN-OS 2.0 and requires an FCIP module.
  • Hardware-based FCIP compression. Cisco enhanced its existing software-based compression and added hardware-based FCIP compression. Although compression ratios vary widely depending on data types, Bhardwaj says that the maximum compression ratio for software-based compression over low-bandwidth links is about 30:1, and 10:1 for hardware-based compression. Realistically, though, he says that a 2x to 6x compression ratio can be expected for either type of compression. For end users, the key benefit is reduced bandwidth costs.
  • Hardware-based IPSec encryption. This marks the first time that Cisco has supported the IPSec security standard in its storage switches. Features include up to 1Gbps per port and support for the Advanced Encryption Standard (AES) with 128-bit or 256-bit keys.

Cisco also introduced a number of features in SAN-OS 2.0 designed to simplify SAN management, including a Web-based "dashboard" for fabric monitoring, the ability for administrators to automatically set up PortChannels and detect configuration errors, a SAN Extension Tuner for optimizing performance of SAN extension applications, and Cisco Fabric Services, which enables SAN automation with fabric-wide consistency, as well as automatic distribution of policies to all switches on the SAN.

The company also added a Distributed Device Alias Services feature that simplifies SAN provisioning and management by replacing cryptic hex names with plain-text names (aliases).

According to a Cisco survey of its largest customers, 90% of the sites plan to use SAN extension for business continuity applications, and 80% of the sites are consolidating their SANs.


MDS 9216i and the MDS 9000 Multi-protocol Services Module

  • Support for Fibre Channel, FCIP, and iSCSI
    • 14 Fibre Channel ports + 2 IP ports (Fibre Channel or iSCSI)
  • SAN extension enhancements
    • Hardware-based FCIP compression
    • Hardware-based IPSec encryption
    • FCIP write and tape acceleration
  • FC over DWDM/CWDM/SONET/SDH enhancements
    • Extended distance
    • 255 to 3,500 buffer credits per Fibre Channel port

    This article was originally published on November 01, 2004