H3C S9500 Series Operation Manual page 96

Operation Manual – DHCP
H3C S9500 Series Routing Switches
Figure 3-4 Sub-option structure
SubOpt: Indicates the number of the sub-option. Sub-options contained in this packet
are sub-option 1, sub-option 2 and sub-option 5. They have the following meanings:
Sub-option 1 defines the Circuit ID.
Sub-option 2 defines the Remote ID.
Sub-option 5 defines the Link Selection.
Len: Indicates the length of the Sub-option Value field.
Sub-option Value: Indicates the sub-option value. For example, the value for sub-option
1 is Circuit ID.
III. Normal mode and fixed network mode
The DHCP relay agent supports Option 82. It can add Option 82 into the request
packets from the clients and forwards them to the server to identify the user location
information. Only sub-option-1 and sub-option 2 can be added while sub-option 5
cannot be added currently. In the normal mode, sub-option 1 defines the layer 2 port
number and VLAN ID of the receiving port, and sub-option 2 defines the MAC address
of the receiving device.
In order to locate the users more exactly, we put forward the IP DSLAM user physical
position location solution for DSLAM application, and define the fixed network mode of
the DHCP Option 82, where the sub-option 1 of Option 82 is expressed in the form of
"Node identifier + frame number/slot number/subslot/port number + vlan", sub-option2
still represents the MAC address of the Relay agent, and sub-option5 is not added.
Chapter 3 DHCP Relay Agent Configuration
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