The sections below describe various legacy boot priority behaviors based on the protocol used.
The client first tries to perform PXE boot and if that fails, it tries iSCSI boot. The client goes to the DHCP to get an IP address. The DHCP server might supply filename (for PXE boot) and root-path (for iSCSI boot) if set by the user.
If the iSCSI target parameters are taken from the flash, then the root-path retrieved from the DHCP is deleted, and if the 'Connect' is set as "Enable" then the values stored in the flash are used (DHCP IP = Enable, DHCP Parameters = Disable).
If a root-path is supplied from either the DHCP or the flash, the client is connected to the iSCSI target, but no boot is performed.
If a filename is supplied, a PXE boot is performed on the Operating System.
If PXE boot failed or no filename was supplied, an iSCSI boot is performed to the connected target.
The client first tries to perform iSCSI boot and if that fails, it tries PXE boot. Upon iSCSI boot one of the following flows occurs:
If all iSCSI configuration is taken from the flash, the client waits 25 seconds for the switches to be configured, and then tries to perform an iSCSI boot (hook to target and then boot). If the boot fails, the client exits. (DHCP IP = disable)
Or
If only the TCP parameters need to be retrieved from the DHCP (DHCP IP = enable, DHCP Parameters = disable), then the IP address is taken from the DHCP, the root-path retrieved from the DHCP is deleted and if the 'Connect' is set as "Enable" then the values stored in the flash are used.
Hook to the iSCSI target.
Try to boot to the iSCSI target.
If iSCSI boot failed and DHCP supplied a filename, try to PXE boot.
If PXE boot failed, exit.
When the legacy boot protocol iSCSI is selected, the following is not supported:
PXE boot after iSCSI boot with static configurations – Setting all iSCSI parameters from the flash (including IP address)
iSCSI boot allows CHAP security option if the following conditions are met:
If 'Connect' = disable or 'CHAP Authentication' = disable, the server ignores both the CHAP Authentication and CHAP Mutual Authentication
If 'Connect' = enable and 'CHAP Authentication' = enable, the target CHAP parameters are used
If 'CHAP Mutual Authentication' = enable, the Initiator CHAP parameters are used