D-Link DGS-3700 user manual Implementation of Dhcp Information Option 82 on the Switch

DGS-3700-12/DGS-3700-12G Series Layer 2 Gigabit Ethernet Switch User Manual

The Implementation of DHCP Information Option 82 on the Switch

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 - 21 Circuit ID and Remote ID Sub-option Format

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