3Com 4200G 12-Port Configuration Manual page 77

Table 1-1 Packet processing of an access port
Processing of an incoming packet
For an untagged packet
Receive the packet and tag
the packet with the default
VLAN tag.
Table 1-2 Packet processing of a trunk port
Processing of an incoming packet
For an untagged packet
If the port has already been
added to its default VLAN, tag
the packet with the default
VLAN tag and then forward
the packet.
If the port has not been added
to its default VLAN, discard
the packet.
Table 1-3 Packet processing of a hybrid port
Processing of an incoming packet
For an untagged packet
If the port has already been
added to its default VLAN,
tag the packet with the
default VLAN tag and then
forward the packet.
If the port has not been
added to its default VLAN,
discard the packet.
For a tagged packet
If the VLAN ID is just the default VLAN
ID, receive the packet.
If the VLAN ID is not the default VLAN
ID, discard the packet.
For a tagged packet
If the VLAN ID is one of the
VLAN IDs allowed to pass
through the port, receive the
packet.
If the VLAN ID is not one of
the VLAN IDs allowed to
pass through the
discard the packet.
For a tagged packet
If the VLAN ID is one of the
VLAN IDs allowed to pass
through the port, receive the
packet.
If the VLAN ID is not one of
the VLAN IDs allowed to
pass through the
discard the packet.
1-6
Processing of an
outgoing packet
Strip the tag from the
packet and send the
packet.
Processing of an outgoing
packet
If the VLAN ID is just the
default VLAN ID, strip off
the tag and send the
packet.
If the VLAN ID is not the
default VLAN ID, keep
the original
port,
unchanged and send the
packet.
Processing of an outgoing
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
port,
VLAN).
tag