HPE 3100 Configuration Manual page 40

Option 82 can contain up to 255 sub-options and must have one sub-option at least. Option 82
supports two sub-options: sub-option 1 (Circuit ID) and sub-option 2 (Remote ID). DHCP snooping
device supports three sub-options: sub-option 1 (Circuit ID), sub-option 2 (Remote ID), and
sub-option 9.
Option 82 has no unified definition. Its padding formats vary with vendors.
There are two methods for configuring Option 82:
•
User-defined method—Manually specify the content of Option 82.
•
Non-user-defined method—Pad Option 82 in the default normal format, verbose format,
private format, or standard format.
NOTE:
Only the DHCP snooping device supports sub-option 9, padded in either private or standard format.
If you choose normal format and verbose format, you can specify the code type for the sub-options
as ASCII or HEX.
•
Normal padding format
Sub-option 1—Contains the VLAN ID and interface number of the interface that received
the client's request. The value of the sub-option type is 1, and that of the circuit ID type is 0.
Figure 21 Sub-option 1 in normal padding format
Sub-option 2—Contains the MAC address of the DHCP relay agent interface or the MAC
address of the DHCP snooping device that received the client's request. The value of the
sub-option type is 2, and that of the remote ID type is 0.
Figure 22 Sub-option 2 in normal padding forma
•
Verbose padding format
Sub-option 1—Contains the user-specified access node identifier (ID of the device that
adds Option 82 in DHCP messages), and the type, number, and VLAN ID of the interface
that received the client's request. The VLAN ID field has a fixed length of 2 bytes. All the
other padding contents of sub-option 1 are length variable. See
Figure 23 Sub-option 1 in verbose padding forma
Sub-option 2—Contains the MAC address of the DHCP relay agent interface or the MAC
address of the DHCP snooping device that received the client's request. It has the same
format as that in normal padding format. See
t
t
Figure 22.
30
Figure 23.