Default Actions on Protocol Packets

The following table lists the default actions on protocol packets when no actions (such as link-protocol forwarding, link-protocol discard, link-protocol transport, l2protocol-tunnel, or protocol enabling) are imposed on them on a device.

When a main interface executes transparent transmission on a protocol packet sent to its sub-interface:
- The sub-interface processes the protocol packet as a normal traffic packet if the packet's VLAN information meets the VLAN configuration of the sub-interface (C-STP and S-STP are discarded).
- The sub-interface discards the protocol packet if the packet's VLAN information does not meet the VLAN configuration of the sub-interface.
When a main interface performs the discard action on a protocol packet sent to its sub-interface, the sub-interface discards the protocol packet.
When the action of a main interface on a protocol packet to be sent to the main interface's sub-interface is sending the packet to the CPU, the sub-interface sends the protocol packet to the CPU.
In access-port mode, only untagged protocol packets are permitted.