4000 Router Series Layer 2 - LAN Switching Configuration Guide

Configuring port-based VLANs

Introduction to port-based VLAN

Port-based VLANs group VLAN members by port. A port forwards packets 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 packets 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.

• A trunk port can carry multiple VLANs to receive and send packets for them.

Except packets from the port VLAN ID (PVID), packets sent through a trunk port will be

VLAN-tagged. Usually, ports connecting network devices are configured as trunk ports.

• A hybrid port allows traffic of some VLANs to pass through untagged and traffic of some other

VLANs to pass through tagged.

Usually, hybrid ports are configured to connect devices whose support for identifying

VLAN-tagged packets is uncertain.

PVID

By default, VLAN 1 is the PVID for all ports. You can configure the PVID for a port, as required.

Use the following guidelines when configuring the PVID on a port:

• 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 can carry multiple VLANs, and you can configure a PVID for the port.

• You can use a nonexistent VLAN as the PVID for a hybrid or trunk port, but not for an access port.

After you remove the VLAN that an access port resides in with the undo vlan command, the PVID

of the port changes to VLAN 1. However, the removal of the VLAN specified as the PVID of a trunk

or hybrid port does not affect the PVID setting on the port.

HP recommends setting the same PVID for local and remote ports.

Make sure a port is assigned to its PVID. Otherwise, when the port receives frames tagged with the PVID

or untagged frames, the port filters out these frames.

How ports of different link types handle frames

Actions Access Trunk

brid

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.