D-Link DES-3526 - Switch - Stackable - The Implementation of DHCP Information Option 82 in the Xstack DES-3500 Series Switches

xStack
®
DES-3500 Series Layer 2 Stackable Fast Ethernet Managed Switch User Manual
137
The Implementation of DHCP Information Option 82 in the xStack
®
DES-3500
Series switches
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:
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.
Remote ID sub-option format 2 (Using user-defined string as remote ID):
1. 2. 3. 4. 5.
2 n+2 1 n User-defined String
1 byte 1 byte 1 byte 1 byte 6 bytes
1. Sub-option type
2. Length: the string length of the Remote ID suboption
3. Remote ID type
4. Length: the string length of user-defined string
5. User-defined string
Figure 6- 121. Circuit ID and Remote ID Sub-option Format