D-Link xStack - The Implementation of DHCP Information Option 82

xStack
®
DGS-3400 Series Layer 2 Gigabit Ethernet Managed Switch
53
The Implementation of DHCP Information Option 82
The config dhcp_relay option_82 command configures the DHCP relay agent information option 82 setting of the switch. The
formats for the circuit ID sub-option and the remote ID sub-option are as follows:
NOTE: For the circuit ID sub-option of a standalone switch, the module field is always zero.
Circuit ID sub-option format:
1. 2. 3. 4. 5. 6. 7.
1 6 0 4 VLAN Module Port
1 byte 1 byte 1 byte 1 byte 2 bytes 1 byte 1 byte
a. Sub-option type
b. Length
c. Circuit ID type
d. Length
e. VLAN: the incoming VLAN ID of DHCP client packet.
f. Module: For a standalone switch, the Module is always 0; For a stackable switch, the Module is the Unit ID.
g. Port: The incoming port number of DHCP client packet, port number starts from 1.
Remote ID sub-option format:
1. 2. 3. 4. 5.
2 8 0 6 MAC address
1 byte 1 byte 1 byte 1 byte 6 bytes
1. Sub-option type
2. Length
3. Remote ID type
4. Length
5. MAC address: The Switch’s system MAC address.
Figure 2 - 51 Circuit ID and Remote ID Sub-option Format