Cisco 350 Series Administration Manual page 283

VLAN Management
Cisco 350, 350X and 550X Series Managed Switches, Firmware Release 2.4, ver 0.4
Interaction with Other Features
This section describes the interaction between private VLANs and other system features.
Features Supported on Private VLAN
The following features can only be enabled on a primary VLAN (and not on an isolated or
community VLAN), although they affect all VLANs in the private VLAN.
• IGMP snooping and MLD snooping. IGMP reports and queries are detected on all the
VLANs in the private VLAN, while the resulting Multicast entries are only added to
the primary VLAN's FDB. This is done to allow Multicast traffic to be forwarded
rather than flooded on the primary VLAN. The isolated and community VLANs
continue to flood Multicast traffic.
• DHCP snooping.
• ARP Inspection.
• IP Source Guard.
The system prevents adding or removing isolated or community VLANs to a private VLAN,
while the above features are enabled.
Features Not Supported on Private VLAN
The following features are not supported on private VLANs and on all the VLANs comprising
the private VLAN:
• Auto Voice VLAN
• Default VLAN
• DHCP Relay
• 802.1x Unauthenticated VLAN
• Guest VLAN
• IPv4 and IPv6. Both can be defined on a primary VLAN. Isolated and community
ports do not allow for IP connectivity. IP connectivity requires traffic to pass on a
primary VLAN.
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