562 Configuring VLANs
Promiscuous Ports
An endpoint connected to a promiscuous port is allowed to communicate 
with any endpoint within the private VLAN. Multiple promiscuous ports can 
be defined for a single private VLAN domain.
In the configuration shown in Figure 22-3, the port connected from SW1 to 
R1 (TE1/1/1) is configured as a promiscuous port. It is possible to configure a 
port-channel as a promiscuous port in order to provide a level of redundancy 
on the private VLAN uplink.
Isolated Ports
An endpoint connected to an isolated port is allowed to communicate with 
endpoints connected to promiscuous ports only. Endpoints connected to 
adjacent isolated ports cannot communicate with each other.
Community Ports
An endpoint connected to a community port is allowed to communicate with 
the endpoints within a community and can also communicate with any 
configured promiscuous port. The endpoints that belong to one community 
cannot communicate with endpoints that belong to a different community, or 
with endpoints connected to isolated ports.
Private VLAN Operation in the Switch Stack and Inter-switch Environment
The Private VLAN feature is supported in a stacked switch environment. The 
stack links are transparent to the configured VLANs; thus, there is no need for 
special private VLAN configuration beyond what would be configured for a 
single switch. Any private VLAN port can reside on any stack member.
To enable private VLAN operation across multiple switches that are not 
stacked, trunk ports must be configured between the switches to transport 
the private VLANs. The trunk ports must be configured with the 
promiscuous, isolated, and community VLANs. Trunk ports must also be 
configured on all devices separating the switches.
In regular VLANs, ports in the same VLAN switch traffic at L2. However, for a 
private VLAN, the promiscuous port forwards received traffic to secondary 
ports in the VLAN (isolated and community). Community ports forward