Indicates the VLAN-based forwarding policy for the unknown unicast packets.
Options:
1. forward(1) -indicates that the unknown unicast packets are transparently transmitted.
2. discard(2) -indicates that the unknown unicast packets are discarded.
During the creation of a VLAN, if this leaf is not specified, forward(1) is adopted by default.
You can perform the set operation on this leaf to modify the VLAN-based
forwarding policy for the unknown unicast packets.
The VLAN-based forwarding policy for the unknown unicast packets can also be
configured in hwPolicyUnknowncast of hwVlanSrvProfTable. If a VLAN service profile is bound
to the VLAN, the configuration in the VLAN service profile takes effect.