Option 82, or ‟Relay Information Option” is a field in DHCP messages used to identify the subscriber. The Option 82 field can already be filled in when a DHCP message is received at the router, or it can be empty. If the field is empty, the router should add identifying information (circuit ID, remote ID or both). If the field is not empty, the router can decide to replace it.
The following is a sample of a partial BSA configuration with Option 82 adding on a VPLS service. Note that snooping must be enabled explicitly on a SAP or a SDP, as applicable. DHCP snooping configuration on an SDP is supported only on the 7210 SAS-K 2F6C4T and 7210 SAS-K 3SFP+ 8C.
*A:7210SAS>config>service#
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vpls 2 customer 1 create
shutdown
stp
shutdown
exit
sap 1/1/12:100 create
dhcp //Configuration example to add option 82
option
action replace
circuit-id
no remote-id
exit
no shutdown
exit
exit
no shutdown
exit
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*A:7210SAS>config>service#
The following example displays an example of a partial BSA configuration to remove
the Option 82 on a VPLS service.
vpls 2 customer 1 create
stp
shutdown
exit
sap 1/1/14:100 create //Configuration example to remove option 82
dhcp
snoop
no shutdown
exit
exit