Dell Brocade Adapters - Manual (Page 149)

Brocade Adapters Installation and Reference Manual 121
53-1002144-01
Network boot
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Booting servers over the network can significantly streamline server administration and facilitate
server deployment. Instead of manually configuring each individual server, boot images on
LAN-based systems can be cloned and assigned to groups of servers at the same time. This not
only simplifies initial configuration, but makes ongoing software updates and maintenance much
easier to administer. When boot images are centrally managed on the network, server security,
integrity, and ability to recover data are also enhanced.
Following are additional benefits of booting over the network:
• Disaster recovery.
• More control and efficiency for software distribution.
• Booting diskless systems such as thin clients and dedicated systems.
• Automating system maintenance such as backups.
• Automating system checking such as virus scanning.
• Ensuring security where a guaranteed secure system is needed.
• Centralized storage management and administration of client workstations.
• Increased host reliability since operating system boots from highly available devices.
• Improved security.
Brocade BIOS support for network boot
The PXE mechanism, embedded in the adapter firmware, provides the ability to boot the host
operating system from a remote system located on the Ethernet LAN instead of the over the SAN or
from the host’s local disk. UNDI (universal network device interface) is an application program
interface (API) used by the PXE protocol to enable basic control of I/O. It performs other
administrative chores like setting up the MAC address and retrieving statistics through the adapter.
UNDI drivers are embedded in the adapter firmware.
When PXE boot or PXE BIOS is enabled, the following occurs to execute the system boot process:
• The PXE client (or adapter) uses the Dynamic Host Configuration Protocol (DHCP) protocol to
obtain information on available PXE boot servers on the network, such as the IP addresses,
from a DHCP server.
• The client contacts the appropriate boot server and obtains the file path for a network
bootstrap program (NBP).
• The client downloads the NBP into the system’s RAM using Trivial File Transfer (TFTP), verifies
it, and finally executes it.
• The PXE protocol sets the proper execution environment, such as availability of basic network
IO services and areas of client memory, then transfer control to the NBP.
• The NBP loads other files, such as configuration files and executable files. This action can run
diagnostics, execute firmware update utilities, or boot an entire operating system over the
network.
The PXE boot client is implemented in the adapter firmware. It supports legacy BIOS for servers
that do not support UEFI or UEFI for the newer servers. The Client PXE code provides the following
services for use by BIOS or a downloaded NBP.
• Preboot Services API
This provides several global control and information functions.