Brocade Network OS Administrator’s Guide v4.1.1 - Manual (Page 50)

configuration. For node replacement in logical chassis cluster mode, the switch is set to the default
configuration.
NOTE
The DAD process is disruptive to traffic.
You must be using DHCP to use DAD. You utilize the DHCP process to retrieve certain parameters
(for example, the firmware path, VCS ID, VCS mode, RBridge ID, and preset configuration file) needed
by the DAD process to perform the firmware and configuration downloads. Currently, only DHCPv4 is
supported.
You must enable DAD from the CLI, after which the switch is rebooted automatically. After the DAD
process is triggered and completed, DAD is automatically disabled. If you attempt to download new
firmware that is already installed on the switch, the DAD process is aborted.
NOTE
If DAD is enabled, you are warned when initiating a firmware download from the CLI that the firmware
download will be unsuccessful.
After a firmware download begins, DAD will report firmware download success or failure status.
DAD depends on DHCP automatic firmware download to load the firmware and configuration onto the
switch. For this to occur, you must first adhere to the following dependencies:
• The management interface of the switch must be set up as DHCP. After setting up the management
interface on a switch in either standalone or fabric cluster mode, you must use the copy running-
config startup-config for the configuration to take effect.
• The DHCP server must have the FTP server IP address and configuration file path.
• The configuration file is on the FTP server and it contains the firmware path, new configuration file
path, VCS ID, VCS mode, and RBridge ID.
DAD supports the following typical use cases:
• Invoking a firmware upgrade (and optional configuration download) on many switches at the same
time in standalone and fabric cluster mode.
• Replacing a switch in a cluster by upgrading the firmware and setting up the switch to a preset
configuration. (In this instance, DAD must be completed on the new switch hardware (in order to
update the firmware) before the new switch can be incorporated into the cluster.)
Note the following considerations when using DAD:
• The DAD process is disruptive.
• Configuration download is not supported during a firmware downgrade.
• Configurations are not downloaded if the DAD process is aborted due to a sanity check failure, or if
you are downloading the same firmware version before the firmware download started.
• If an existing firmware download session is either occurring or paused, such as during a firmware
commit, DAD is not triggered. Instead, the last firmware download session continues. If a firmware
download is in progress and you attempt to enable DAD, you are prompted to try again later.
• In-Service Software Upgrade (ISSU) is not supported at this time.
• For dual management module (MM) chassis, the dual MM must be in sync from the chassis bootup
(not from HA failover). In a chassis system, both MMs are rebooted at the same time.
Basic Switch Management
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