Assigning An Ethernet Port To Specified Vlans; Configuring The Default Vlan Id For A Port - 3Com 4500 PWR 26-Port Configuration Manual

The three types of ports can coexist on the same device.

Assigning an Ethernet Port to Specified VLANs

You can assign an Ethernet port to a VLAN to forward packets for the VLAN, thus allowing the VLAN on
the current switch to communicate with the same VLAN on the peer switch.
An access port can be assigned to only one VLAN, while a hybrid or trunk port can be assigned to
multiple VLANs.
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 6-1 Packet processing of an access port
For an untagged packet
Receive the packet and tag
the packet with the default
VLAN tag.
Table 6-2 Packet processing of a trunk port
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.
Processing of an incoming 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.
Processing of an incoming packet
For a tagged 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.
6-5
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.
tag