3Com E4500-24, Cli Configuration Manual

Page: 77 / 848

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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
If the VLAN ID is just the
default VLAN ID, strip off the
tag and send the packet.
z
If the VLAN ID is not the
default VLAN ID, keep the
original tag unchanged and
send the packet.
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).