H3C Technologies H3C S3100 Series Switches - Manual (Page 88)

1-6
Before assigning an access or hybrid port to a VLAN, create the VLAN first.
Configuring the Default VLAN ID for a Port
An access port can belong to only one VLAN. Therefore, the VLAN an access port belongs to is also the
default VLAN of the access port. A hybrid/trunk port can belong to multiple VLANs, so you should
configure a default VLAN ID for the port.
After a port is added to a VLAN and configured with a default VLAN, the port receives and sends
packets in a way related to its link type. For detailed description, refer to the following tables:
Table 1-1 Packet processing of an access port
Processing of an incoming packet
For an untagged packet For a tagged packet
Processing of an
outgoing packet
Receive the packet and tag the
packet with the default VLAN tag.
z If the VLAN ID is just the default VLAN ID,
receive the packet.
z If the VLAN ID is not the default VLAN ID,
discard the packet.
Strip the tag from the
packet and send the
packet.
Table 1-2 Packet processing of a trunk port
Processing of an incoming packet
For an untagged packet For a tagged packet
Processing of an outgoing
packet
z If the port has already been
added to its default VLAN, tag the
packet with the default VLAN tag
and then forward the packet.
z If the port has not been added to
its default VLAN, discard the
packet.
z If the VLAN ID is one of the
VLAN IDs allowed to pass
through the port, receive the
packet.
z If the VLAN ID is not one of the
VLAN IDs allowed to pass
through the port, discard the
packet.
z Remove the tag and send
the frame if the frame carries
the default VLAN tag and the
port belongs to the default
VLAN.
z Send the frame without
removing the tag if its VLAN
is carried on the port but is
different from the default
one.
Table 1-3 Packet processing of a hybrid port
Processing of an incoming packet
For an untagged packet For a tagged packet
Processing of an outgoing
packet
z If the port has already been
added to its default VLAN, tag
the packet with the default
VLAN tag and then forward the
packet.
z If the port has not been added
to its default VLAN, discard the
packet.
z If the VLAN ID is one of the
VLAN IDs allowed to pass
through the port, receive the
packet.
z If the VLAN ID is not one of the
VLAN IDs allowed to pass
through the port, discard the
packet.
Send the packet if the VLAN ID is
allowed to pass through the port.
Use the port hybrid vlan command
to configure whether the port keeps
or strips off the tags when sending
packets of a VLAN (including the
default VLAN).