Type of access node identifier that is used to fill
in the circuit ID suboption of option 82 when the value
of hh3cDhcpRelay2IfOpt82CIDMode is set to 'verbose'.
The SET operation of this object must be with the SET
operation of hh3cDhcpRelay2IfOpt82CIDMode.
'invalid' indicates that the node identifier is NOT used
to fill in the circuit ID suboption of option 82.
If the value of hh3cDhcpRelay2IfOpt82CIDMode is NOT 'verbose',
the value of this object is set to 'invalid' automatically.
Otherwise the value of this object cannot be set to 'invalid'.
'mac' indicates that the node identifier is filled in with
the MAC of DHCP relay input interface.
If the value of hh3cDhcpRelay2IfOpt82CIDMode is set to
'verbose', the default value of this object is 'mac'.
'sysname' indicates that the node identifier is filled in with
the sysname of the DHCP relay device.
'userDefine' indicates that the node identifier is filled in with
the string defined by the object of hh3cDhcpRelay2IfOpt82CIDNodeStr.
If the value is set to 'userDefine', the value of
hh3cDhcpRelay2IfOpt82CIDNodeStr must be set to a non-zero
length string simultaneously.