R2511-HP MSR Router Series Layer 3 - IP Services Configuration Guide(V5)

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Figure 16 Sub-option 2 in normal padding format
• Verbose padding format:
{ Sub-option 1—Includes 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 17.
Figure 17 Sub-option 1 in verbose pa
dding format
{ Sub-option 2—Includes 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 Figure 16.
• Pr
ivate padding format:
{ Sub-option 1—Includes the VLAN ID of the interface that received the client's request, module
(subcard number of the receiving port on a centralized device or slot number of the receiving
port on a distributed device) and port (number of the receiving port). The value of the sub-option
type is 1.
Figure 18 Sub-option 1 in private padding format
{ Sub-option 2—Includes the MAC address of the DHCP snooping device that received the
client's request. The value of the sub-option type is 2.
Figure 19 Sub-option 2 in private padding format
{ Sub-option 9—Includes the sysname and the primary IP address of the Loopback0 interface.
The value of the sub-option type is 9.