284 CHAPTER 17: NETWORK PROTOCOL OPERATION
■Len: Specifies the Length of the agent information field.
■Agent information field: Specifies the sub-options used.
2Sub-option format
Figure 68 illustrates the sub-option format.
Figure68 Sub-option format
■SubOpt: Sub-option number. Currently, the value of this sub-field can be 1, 2, and
5, which have the following meanings:
1 represents this sub-option is for agent circuit ID (Circuit ID);
2 represents this sub-option is for remote agent ID (Remote ID);
5 represents this sub-option is for link selection.
■Len: Length of the Sub-option value sub-filed.
■Sub-option value: Value of the sub-option. For example, the value for sub-option 1
is Circuit ID.
3Related specification
The following are the RFCs concerning option 82 supporting.
■RFC2131 Dynamic Host Configuration Protocol
■RFC3046 DHCP Relay Agent Information Option