Vendor-specific option (Option 43)
Option 43 function
DHCP servers and clients use Option 43 to exchange vendor-specific configuration information.
The DHCP client can obtain the following information through Option 43:
ACS parameters, including the ACS URL, username, and password.
Service provider identifier, which is acquired by the CPE from the DHCP server and sent to the ACS for selecting vender-specific configurations and parameters. For more information about CPE and ACS, see Network Management and Monitoring Configuration Guide.
PXE server address, which is used to obtain the boot file or other control information from the PXE server.
Option 43 format
Figure 14: Option 43 format
Network configuration parameters are carried in different sub-options of Option 43 as shown in Figure 14.
Sub-option type—The field value can be 0x01 (ACS parameter sub-option), 0x02 (service provider identifier sub-option), or 0x80 (PXE server address sub-option).
Sub-option length—Excludes the sub-option type and sub-option length fields.
Sub-option value—The value format varies by sub-option.
Sub-option value field format
ACS parameter sub-option value field—Includes the ACS URL, username, and password separated by spaces (hexadecimal number 20) as shown in Figure 15.
Figure 15: ACS parameter sub-option value field
Service provider identifier sub-option value field—Includes the service provider identifier.
PXE server address sub-option value field—Includes the PXE server type that can only be 0, the server number that indicates the number of PXE servers contained in the sub-option, and server IP addresses, as shown in Figure 16.
Figure 16: PXE server address sub-option value field
