This restriction prevents communication between an isolated VLAN and a promiscuous port on the FEX.
However, as host interfaces are not intended to be connected to another switch or router, you cannot enable
a promiscuous port on a FEX.
Broadcast Traffic in Private VLANs
Broadcast traffic from ports in a private VLAN flows in the following ways:
•
The broadcast traffic flows from a promiscuous port to all ports in the primary VLAN (which includes
all the ports in the community and isolated VLANs). This broadcast traffic is distributed to all ports
within the primary VLAN, including those ports that are not configured with private VLAN parameters.
•
The broadcast traffic from an isolated port is distributed only to those promiscuous ports in the primary
VLAN that are associated to that isolated port.
•
The broadcast traffic from community ports is distributed to all ports within the port
’
s community and
to all promiscuous ports that are associated to the community port. The broadcast packets are not
distributed to any other communities within the primary VLAN or to any isolated ports.
Private VLAN Port Isolation
You can use PVLANs to control access to end stations as follows:
•
Configure selected interfaces connected to end stations as isolated ports to prevent any communication.
For example, if the end stations are servers, this configuration prevents communication between the
servers.
•
Configure interfaces connected to default gateways and selected end stations (for example, backup
servers) as promiscuous ports to allow all end stations access to a default gateway.
Configuring a Private VLAN
Enabling Private VLANs
You must enable PVLANs on the switch to use the PVLAN functionality.
The PVLAN commands do not appear until you enable the PVLAN feature.
Note
Procedure
Purpose
Command or Action
Enters global configuration mode.
switch#
configure terminal
Step 1
Enables the PVLAN feature on the switch.
switch(config)#
feature private-vlan
Step 2
Cisco Nexus 6000 Series NX-OS Layer 2 Switching Configuration Guide, Release 7.x
34
Configuring Private VLANs
Broadcast Traffic in Private VLANs