E-Tree and Private VLAN topology

Table 1. E-Tree and Private VLANs product support
Feature	Product	Release introduced
E-Tree and Private VLANs	5320 Series	Fabric Engine 8.6
	5420 Series	VOSS 8.4
	5520 Series	VOSS 8.2.5
	5720 Series	Fabric Engine 8.7
	7520 Series	Fabric Engine 8.10
	7720 Series	Fabric Engine 8.10
	VSP 4900 Series	VOSS 8.1
	VSP 7400 Series	VOSS 8.0
Routing on Private VLANs	5320 Series	Fabric Engine 8.6
	5420 Series	VOSS 8.5
	5520 Series	VOSS 8.5
	5720 Series	Fabric Engine 8.7
	7520 Series	Fabric Engine 8.10
	7720 Series	Fabric Engine 8.10
	VSP 4900 Series	VOSS 8.5
	VSP 7400 Series	VOSS 8.5

Ethernet Private Tree (E-Tree) extends Shortest Path Bridging MAC (SPBM) to Private VLANs (PVLAN).

Transport within the SPBM network is achieved by associating the private VLAN with an I-SID. Flooded traffic from both promiscuous and isolated devices is transported over the same I-SID multicast tree and suppression for spoke-to-spoke traffic is done on the egress SPB Backbone Edge Bridge (BEB). This means the Private VLAN IDs are globally significant and must be the same on all BEBs

The following list provides details for E-Tree and Private VLAN topology:

E-Tree associates a Private VLAN with an I-SID.
Note

The same I-SID could be attached to a regular VLAN. In that case, all ports on the regular VLAN behave like Promiscuous ports on the PVLAN.
Other SPB BEBs can associate a regular CVLAN to the same I-SID that E-Tree uses.
Note

The CVLAN ID must match the primary PVLAN ID.
CVLAN devices assigned to the same I-SID that E-Tree uses have Promiscuous connectivity within the segment.

The following figure shows a basic E-Tree network topology consisting of groups of private VLANs connected by the SPBM core network.

Private VLAN port types

The private VLAN port type is isolated, promiscuous, or trunk. If the port is a member of an MLT, then the port inherits the private VLAN type of the MLT.

In terms of network topology, the isolated port is considered a spoke. The isolated port, or spoke, does not communicate with any other isolated port in the network. The isolated port only communicates with the promiscuous ports, or hubs.

E-Tree and Private VLAN limitations

The following limitations apply to E-Tree and Private VLAN topology:

A port that is of Private VLAN type trunk must be tagged. Isolated and Promiscuous Private VLAN ports can be either tagged or untagged.
When a port or MLT that has a Private VLAN type set to Isolated or Promiscuous is added to a private VLAN, if that port is used by other non private VLANs, then those non private VLANs are removed.
Private VLAN type Isolated or Promiscuous and Flex-UNI are mutually exclusive on MLT ports.
A port which is Private VLAN type Isolated and is tagged can belong to only one Private VLAN.