Administrator Guide

Layer 3 Routing Commands 1453
Default Configuration
There is no default option configured.
Command Mode
DHCP Pool Configuration mode
User Guidelines
The option information must match the selected option type and length.
Options cannot be longer than 255 characters in length. The option
information is conveyed in the TLV specified by the code parameter in the
DHCP OFFER, DHCP ACK, DHCP INFORM ACK and DHCP
BOOTREPLY messages.
Option 125 strings must conform to the relevant TLV format as specified in
RFC 3925 beginning with a 2 byte pad filled in by the switch (option code
125 and option length), the 2 byte enterprise number, the data length and the
sub-option values. For example, option 125 might be written on the
command line as:
option 125 hex 0000.02a2.1205.1061.7574.6f69.6e73.7461.6c6c.5f64.6863.70
which translates to:
• 0x0000 - Two byte pad filled in by switch (option-code 125 and option-len)
• 0x02A2 - Dell Vendor code 674
• 0x12 - TLV length - 18 bytes
• 0x05 - Sub-option code 5
• 0x10 - Sub-option length - 16 bytes
• 0x6175746f696e7374616c6c5f646863.70 - Sub-option value
"autoinstall_dhcp"
Options that accept only fixed length strings need only have the relevant data
bytes specified on the command line. The switch will build the TLV and
insert the specified data bytes into the option. Refer to the relevant
documentation for the DHCP client to identify what information, if any, is
accepted by the client in DHCP Option 125.
2CSNXXX_SWUM204.book Page 1453 Monday, January 25, 2016 1:25 PM