Netgear XCM8806 Chassis User Manual - Page 259

NETGEAR 8800 User Manual Note: The formula above estimates the worst-case scenario for the maximum number of FDB entries for a single PVLAN. If the switch supports additional PVLANs, apply the formula to each PVLAN and add the totals for all PVLANs. If the switch also support standard VLANs, there will also be FDB entries for the standard VLANs. Layer 3 Communications For PVLANs, the default switch configuration controls Layer 3 communications exactly as communications are controlled in Layer 2. For example, Layer 3 communications is enabled between ports in a non-isolated subscriber VLAN, and disabled between ports in an isolated subscriber VLAN. Ports in a non-isolated subscriber VLAN cannot communicate with ports in other non-isolated subscriber VLANs. You can enable Layer 3 communications between all ports in a PVLAN. For more information, see Managing Layer 3 Communications in a PVLAN on page 263. PVLAN Limitations The Private VLAN feature has the following limitations: • Requires more FDB entries than a standard VLAN • Within the same VR, VLAN tag duplication is not allowed • Within the same VR, VLAN name duplication is not allowed • Each MAC address learned in a PVLAN must be unique. A MAC address cannot exist in two or more VLANs that belong to the same PVLAN. • MVR cannot be configured on PVLANs. • A PBB network (BVLAN) cannot be added to a PVLAN. • STP can only be configured on network VLAN ports (and not on subscriber VLAN ports). To support STP on the network VLAN, you must add all of the VLANs in the PVLAN to STP. • There is no NetLogin support to add ports as translate to the network VLAN, but the rest of NetLogin and the PVLAN feature do not conflict. • IGMP snooping is performed across the entire PVLAN, spanning all the subscriber VLANs, following the PVLAN rules. For VLANs that are not part of a PVLAN, IGMP snooping operates as normal. • When two switches are part of the same PVLAN, unicast and multicast traffic require a tagged trunk between them that preserves tags (no tag translation). • Subscriber VLANs in a PVLAN cannot exchange multicast data with VLANs outside the PVLAN and with other PVLANs. However, the network VLAN can exchange multicast data with VLANs outside the PVLAN and with network VLANs in other PVLANs. An additional limitation applies to the NETGEAR 8800 switches. If two or more member VLANs have overlapping ports (where the same ports are assigned to both VLANs), each additional VLAN member with overlapping ports must have a dedicated loopback port. To Chapter 9. VLANs | 259