Default VLAN
Each port can be configured with a default VLAN identified by the port VLAN ID (PVID). The
meaning of the default VLAN varies according to the port type.
For details on different PVIDs and methods of processing Ethernet frames, see
processing based on the port type
.
3.2.2 VLAN Assignment
VLAN assignment can be based on interface numbers, and VLAN frames are processed
depending on the interface type.
The network administrator configures a port default VLAN ID (PVID), that is, the default VLAN
ID, for each port on the switching device. That is, a port belongs to a VLAN by default.
l
When a data frame reaches a port, it is marked with the PVID if the data frame carries no
VLAN tag and the port is configured with a PVID.
l
If the data frame carries a VLAN tag, the switching device will not add a VLAN tag to the
data frame even if the port is configured with a PVID.
3.2.3 Principle of VLAN Communication
Basic Principle of VLAN Communication
To improve the efficiency in processing frames, frames within a switch all carry VLAN tags for
uniform processing. When a data frame reaches a port of the switch, if the frame carries no
VLAN tag and the port is configured with a PVID, the frame is marked with the port's PVID. If
the frame has a VLAN tag, the switch will not mark a VLAN tag for the frame regardless of
whether the port is configured with a PVID.
The switch processes frames differently according to the type of port receiving the frames. The
following describes the frame processing according to the port type.
Table 3-2
Frame processing based on the port type
Port
Type
Untagged Frame
Processing
Tagged Frame
Processing
Frame
Transmission
Access
port
Accepts an untagged frame
and adds a tag with the
default VLAN ID to the
frame.
l
Accepts the tagged
frame if the frame's
VLAN ID matches the
default VLAN ID.
l
Discards the tagged
frame if the frame's
VLAN ID differs from
the default VLAN ID.
After the PVID tag is
stripped, the frame is
transmitted.
Huawei AR530&AR550 Series Industrial Switch Routers
Configuration Guide - Ethernet Switching
3 VLAN Configuration
Issue 01 (2014-11-30)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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