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2007 Daylight Saving Time Change Impact on Fibre Channel Switches and Routers Sold by Sun

This paper addresses the U.S. change in Daylight Saving Time (DST) and its affect on Fibre Channel switch and router products sold by Sun. Switches located outside the U.S. are not affected by U.S. DST law changes and do not need to change or update as a result.

2007 DST change:
Beginning in 2007, the U.S. will begin Daylight Saving Time at 2:00 a.m. on the second Sunday in March and revert to standard time on the first Sunday in November.

Background on FC Switches/Routers related to DST:
FC switches are, in some cases, time aware devices. Depending on the manufacturer, the maintenance of time can be a function of the switch hardware or fabric management software. FC switches primarily use time for use as timestamps in event logging. Some fabric management software may also use time to start the execution of policy based tasks or events. It is generally accepted that maintaining a consistent time base across the SAN fabric is a best practice. In no case, however, will the switch or router stop operating or interrupt I/O traffic due to a DST setting error.

Sun Fibre Channel Switch Information by Vendor
Sun currently sells FC switches from McDATA, Brocade, QLogic, and Cisco. Each of these switch vendors has different implementations of time management and thus there are a variety of fixes or patches to implement the required changes for the 2007 DST change.

FOS 5.2.0a or FOS 5.0.5b
SAN-OS (all)
Patch ID
124898-01 or 119552-04
March 2007
Firmware update required for DST change.
Use Network Time Protocol server or use CLI to set summer-time configuration.
Switch time synchronizes to EFCM time. EFCM time set by server.
Releases March 9th

  • Brocade
    Download and install appropriate firmware from SunSolve.

  • Cisco
    Use NetworkTimeProtocol (NTP) server or execute CLI command on each switch to reconfigure DST using the 'clock summer-time' command. See Cisco documentation for CLI details.

  • McDATA
    Confirm that the machine which runs EFCM is configured to properly set DST time. This will automatically configure 10000 and 6000 series directors as well as 4000 and 3000 series switches. If not using EFCM, the user can set time manually and for routers running E/OSi, the user can set the time manually or use NetworkTimeProtocol (NTP).

  • QLogic
    Download and install appropriate firmware from SunSolve.