H3C Technologies H3C S12500 Series Switches - Manual (Page 19)

6
Configuring port-based VLANs
Introduction to port-based VLANs
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
You can configure the link type of a port as access, trunk, or hybrid. The link types use the following
VLAN tag handling methods:
• An access port belongs to only one VLAN and sends traffic untagged.
It is usually used to connect a terminal device unable to recognize VLAN tagged-packets or when
there is no need to separate different VLAN members. As shown in
Figure 5 , Device A is connected
to common PCs that cannot recognize VLAN tagged-packets, and you must configure Device A’s
ports that connect the PCs as access ports.
• A trunk port can carry multiple VLANs to receive and send traffic for them.
Except traffic of the port VLAN ID (PVID), traffic sent through a trunk port will be VLAN tagged.
Usually, ports connecting network devices are configured as trunk ports. As shown in Figure 5 ,
because Device A and Device B need to transmit packets of VLAN 2 and VLAN 3, you must
configure the ports connecting Device A and Device B as trunk ports, and assign them to VLAN 2
and VLAN 3.
• Like a trunk port, a hybrid port can carry multiple VLANs to receive and send traffic for them.
Unlike a trunk port, a hybrid port allows traffic of all VLANs to pass through untagged. Usually,
hybrid ports are configured to connect network devices whose support for VLAN tagged-packets
you are uncertain about. As shown in Figure 5 , Device C connects a small-sized LAN in which
some PCs belong to VLAN 2 while some other PCs belong to VLAN 3. In this case, you must
configure Device B’s port connecting to Device C as a hybrid port that allows packets of VLAN 2
and VLAN 3 to pass through untagged.