H3C Technologies H3C SecPath F1000-E - Manual (Page 393)

3
• Policy
• Other criteria
Because the Web interface is available only for port-based VLANs, this chapter introduces only
port-based VLANs.
Introduction to Port-Based VLAN
Port-based VLANs group VLAN members by port. A port forwards traffic for a VLAN only after it is
assigned to the VLAN.
Port link type
Depending on the tag handling mode, the link type of a port can be one of the following three:
• Access. An access port belongs to only one VLAN. Usually, ports directly connected to PCs are
configured as access ports.
• Trunk. A trunk port can be assigned to multiple VLANs to receive and send traffic for them. Usually,
ports connecting network devices are configured as trunk ports to allow members of the same
VLAN to communicate with each other across multiple network devices.
• Hybrid. A hybrid port can join multiple VLANs to receive and send traffic for them. You can
configure a port connected to a network device or user terminal as a hybrid port for access link
connectivity or trunk connectivity.
Default VLAN
By default, VLAN 1 is the default VLAN for all ports. However, you can change the default VLAN for a
port as required. When doing that, follow these guidelines:
• Because an access port can join only one VLAN, its default VLAN is the VLAN to which it belongs
and cannot be configured.
• Because a trunk or hybrid port can join multiple VLANs, you can configure a default VLAN for the
port.
A port with a default VLAN configured handles a frame as follows:
Actions (in the inbound direction)
Port type
Untagged frame Tagged frame
Actions (in the outbound
direction)
Access
Tag the frame with the
default VLAN tag.
• Receive the frame if its VLAN
ID is the same as the default
VLAN ID.
• Drop the frame if its VLAN ID
is different from the default
VLAN ID.
Remove the default VLAN tag
and send the frame.
Trunk
Check whether the
default VLAN is carried
on the port:
• If yes, tag the frame
with the default VLAN
tag.
• If not, drop the frame.
• Receive the frame if its VLAN
is carried on the port.
• Drop the frame if its VLAN is
not carried on the port.
• Remove the tag and send
the frame if the frame
carries the default VLAN
tag and the port permits
the default VLAN.
• Send the frame without
removing the tag if its
VLAN is carried on the
port but is different from
the default one.