D-Link DES-3552 Инструкция по эксплуатации онлайн [129/260] 40412

DES-3550 Fast Ethernet Layer 2 Switch

NOTE: If the switch receives a packet that contains the option-82 field from a DHCP

client and the information-checking feature is enabled, the Switch drops the packet

because it is invalid. However, in some instances, you might configure a client with the

option-82 field. In this situation, you should disable the information-check feature so that

the switch does not remove the option-82 field from the packet. You can configure the

action that the switch takes when it receives a packet with existing option-82 information

by configuring the DHCP Agent Information Option 82 Policy.

The Implementation of DHCP Information Option 82 in DES-3526

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.

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 6- 87. Circuit ID and Remote ID Sub-option Format

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