BY DAVE SIMPSON
Claiming near wire-speed (1Gbps) performance, eight vendors have banded together to demonstrate cross-country connectivity between storage area networks (SANs) in Sunnyvale, CA, and Newark, NJ. The demonstration was dubbed the "Promontory Project" after the location in Utah where the first transcontinental railroad was joined with a golden spike.
Participating in the project were the following companies:
- Adaptec (iSCSI host bus adapters)
- Dell (servers and Fibre Channel disk arrays)
- Hitachi Data Systems (Fibre Channel disk arrays)
- IBM (iSCSI disk arrays)
- Intel (iSCSI HBAs)
- Nishan Systems (IP Storage switches)
- QLogic (Fibre Channel HBAs)
- Qwest (IP WAN backbone)
Although Cisco did not officially join in the demonstration, a variety of its switches were used in the configuration (see diagram).
The Promontory Project linked iSCSI and Fibre Channel SANs over an IP WAN using protocols such as iFCP and FCIP.
In the demonstration, near-1Gbps (100MBps) speeds were achieved over 2.5Gbps (OC-48) and 10Gbps (OC-192) connections. Although the theoretical maximum speed is 100MBps, actual throughput averaged closer to 80MBps. Cross-country latency was approximately 44 milliseconds in the test.
For more detailed statistics, visit http://stat.qwest.net/index_flash.html.
In addition to Fibre Channel and SCSI, the demonstration took advantage of a variety of emerging IP Storage protocols, including iSCSI, iFCP, and FCIP, that are designed to adapt block-mode SCSI or Fibre Channel traffic to the TCP/IP protocol stack. All of these protocols are in the standards approval process in the Internet Engineering Task Force, with some expected to be approved within the next month or two.
According to John Webster, a senior analyst with the Illuminata research and consulting firm, iSCSI maps the SCSI command set to IP, preserving the command set while replacing its transmission protocol with IP. iFCP is a gateway-to-gateway protocol used to link Fibre Channel devices via TCP/IP links, using TCP for congestion control, error-detection, and recovery. FCIP links Fibre Channel SAN "islands" over IP using encapsulation to send Fibre Channel frames over TCP/IP links.
(For more on IP Storage protocols, see "Fibre Channel vs. IP vs. InfiniBand," InfoStor, July 2001, p. 56, and "Demys tifying iSCSI, iFCP, mFCP, FCIP, and iSNS," InfoStor, September 2001, p. 66.)
According to Tom Clark, director of technical marketing at Nishan, the primary goals of the Promontory Project were to prove long-distance connectivity using block-level storage I/O over IP at gigabit speed and to demonstrate interoperability between various protocols and equipment from different vendors.
Key applications for long-distance IP Storage include remote backup and mirroring, storage consolidation, business continuity and disaster recovery, tape vaulting, database replication, and content distribution.
Compaq and CNT
In a related demonstration, Compaq and Computer Net work Technology (CNT) built a global storage network linking Fibre Channel SANs in Colorado Springs, CO; Nijmegen in the Netherlands; and Sydney, Australia. The Compaq-CNT demo was based on the FCIP protocol and CNT's UltraNet Edge Storage Routers. Data replication and storage network management applications were handled by Compaq's SANworks Data Replication Manager and SANworks management software.