H3C S6850 Series, Configuration Manual

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2
VLAN types
The following VLAN types are available:
•
Port-based VLAN.
•
MAC-based VLAN.
•
IP subnet-based VLAN.
•
Protocol-based VLAN.
If all these types of VLANs are configured on a port, the port processes packets in the following
descending order of priority by default:
•
MAC-based VLAN.
•
IP subnet-based VLAN.
•
Protocol-based VLAN.
•
Port-based VLAN.
Port-based VLANs
Port-based VLANs group VLAN members by port. A port forwards packets from a VLAN only after it
is assigned to the VLAN.
Port link type
You can set the link type of a port to access, trunk, or hybrid. The port link type determines whether
the port can be assigned to multiple VLANs. The link types use the following VLAN tag handling
methods:
•
Access —An access port can forward packets only from one VLAN and send these packets
untagged. An access port is typically used in the following conditions:
{
Connecting to a terminal device that does not support VLAN packets.
{
In scenarios that do not distinguish VLANs.
•
Trunk —A trunk port can forward packets from multiple VLANs. Except packets from the port
VLAN ID (PVID), packets sent out of a trunk port are VLAN-tagged. Ports connecting network
devices are typically configured as trunk ports.
•
Hybrid —A hybrid port can forward packets from multiple VLANs. The tagging status of the
packets forwarded by a hybrid port depends on the port configuration. In one-to-two VLAN
mapping, hybrid ports are used to remove SVLAN tags for downlink traffic. For more
information about one-to-two VLAN mapping, see "Configuring VLAN mapping."
PVID
The PVID identifies the default VLAN of a port. Untagged packets received on a port are considered
as the packets from the port PVID.
An access port can join only one VLAN. The VLAN to which the access port belongs is the PVID of
the port. A trunk or hybrid port supports multiple VLANs and the PVID configuration.
How ports of different link types handle frames
Actions Access Trunk Hybrid
In the inbound
direction for an
untagged frame
Tags the frame with the
PVID tag.
•
If the PVID is permitted on the port, tags the frame with
the PVID tag.
•
If not, drops the frame.
In the inbound
direction for a
tagged frame
•
Receives the
frame if its VLAN
ID is the same as
•
Receives the frame if its VLAN is permitted on the port.
•
Drops the frame if its VLAN is not permitted on the port.