Users Guide

– A primary VLAN has one or more secondary VLANs.
– A primary VLAN and each of its secondary VLANs decrement the available number of VLAN IDs in
the switch.
– A primary VLAN has one or more promiscuous ports.
– A primary VLAN might have one or more trunk ports, or none.
• Secondary VLAN — a subdomain of the primary VLAN.
– There are two types of secondary VLAN — community VLAN and isolated VLAN.
PVLAN port types include:
• Host port — in the context of a private VLAN, is a port in a secondary VLAN. The port must first be
assigned that role in INTERFACE mode.
– Host port that belongs to a community VLAN is allowed to communicate with other ports in the
same community VLAN and with promiscuous ports & Trunk Port in Same PVLAN
– Host port can be part of either community VLAN or isolated VLAN. The bhavior of host port will
change with respect to its presence in community and isolated VLAN.
– Host port that belongs to an isolated VLAN can communicate with promiscuous ports & Trunk
port that are in the same PVLAN
• Promiscuous port — a port that is allowed to communicate with any other port type in the PVLAN. A
promiscuous port can be part of more than one primary VLAN. A promiscuous port cannot be added
to a regular VLAN.
• Trunk port — carries traffic between switches. A trunk port in a PVLAN is always tagged. In tagged
mode, the trunk port carries the primary or secondary VLAN traffic. The tag on the packet helps
identify the VLAN to which the packet belongs. A trunk port can also belong to a regular VLAN (non-
private VLAN).
Each of the port types can be any type of physical Ethernet port, including port channels (LAGs). For
more information about port channels, refer to Port Channel Interfaces in the Interfaces chapter.
For an introduction to VLANs, refer to Layer 2.
Using the Private VLAN Commands
To use the PVLAN feature, use the following commands.
• Enable/disable Layer 3 communication between secondary VLANs.
INTERFACE VLAN mode
[no] ip local-proxy-arp
NOTE: Even after you disable ip-local-proxy-arp (no ip-local-proxy-arp) in a
secondary VLAN, Layer 3 communication may happen between some secondary VLAN hosts,
until the address resolution protocol (ARP) timeout happens on those secondary VLAN hosts.
• Set the mode of the selected VLAN to community, isolated, or primary.
INTERFACE VLAN mode
[no] private-vlan mode {community | isolated | primary}
• Map secondary VLANs to the selected primary VLAN.
INTERFACE VLAN mode
[no] private-vlan mapping secondary-vlan vlan-list
Private VLANs (PVLAN)
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