H3C Technologies H3C WX3000E Series Wireless Switches - Manual (Page 28)

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For more information about DHCP options, see RFC 2132.
Custom options
Some options, such as Option 43, have no unified definitions in RFC 2132.
Vendor-specific option (Option 43)
DHCP servers and clients use Option 43 to exchange vendor-specific configuration information. Upon
receiving a DHCP message requesting Option 43 (in Option 55), the DHCP server replies a message
containing Option 43 to assign vendor-specific information to the DHCP client.
The DHCP client can obtain the following information through Option 43:
• Auto-Configuration Server (ACS) parameters, including the ACS URL, username, and password.
• Service provider identifier, which is acquired by the customer premises equipment (CPE) from the
DHCP server and sent to the ACS for selecting vender-specific configurations and parameters.
• Preboot Execution Environment (PXE) server address, which is used to obtain the bootfile or other
control information from the PXE server.
1. Format of Option 43
Figure 10 Format of Option 43
Network configuration parameters are carried in different sub-options of Option 43 as shown in Figure
10 . The sub-option fields are described as follows:
• Sub-option type: Type of a sub-option. The field value can be 0x01, 0x02, or 0x80. 0x01 indicates
an ACS parameter sub-option. 0x02 indicates a service provider identifier sub-option. 0x80
indicates a PXE server address sub-option.
• Sub-option length: Length of a sub-option excluding the sub-option type and sub-option length
fields.
• Sub-option value: Value of a sub-option.
2. Format of the sub-option value field of Option 43
• As shown in Figure 11 , the value field of the ACS parameter sub-option contains variable ACS URL,
username, and password separated by spaces (0x20).
Figure 11 Format of the value field of the ACS parameter sub-option
• The value field of the service provider identifier sub-option contains the service provider identifier.