Intel PCI User Manual

118

Word 31h contains settings that can be programmed by an OEM or network administrator to 

customize the operation of the software. These settings cannot be changed from within the Control-

S setup menu or the IBA Intel Boot Agent utility. The lower byte contains settings that would 
typically be configured by a network administrator using the Intel Boot Agent utility; these settings 

generally control which setup menu options are changeable. The upper byte are generally settings 

that would be used by an OEM to control the operation of the agent in a LOM environment, 
although there is nothing in the agent to prevent their use on a NIC implementation

4:3

DBS

Default Boot Selection. These bits select which device is the default 
boot device. These bits are only used if the agent detects that the BIOS 
does not support boot order selection or if the MODE field of word 31h 
is set to MODE_LEGACY.
00b = Network boot, then local boot
01b = Local boot, then network boot
10b = Network boot only
11b = Local boot only

2

BBS

BIOS Boot Specification (OBSOLETE). In previous versions of the 
agent, this bit enables or disables use of the BBS to determine boot 
order. If set to 1b, the BIOS boot order is used, and the DBS bits are 
ignored. The boot agent at runtime no longer uses this bit. The runtime 
checks for BBS/PnP and the setting in the MODE field of word 31h are 
used instead.

1:0

PS

Protocol Select. These bits select the boot protocol.
00b = PXE (default value) 
01b = RPL protocol 
Other values are undefined.