but from the need to constrain broadcast behavior as a result of flooding. It is therefore possible to assign a range of VLAN identifiers containing V identifiers as only locally significant to a given MAC address. It is then easy to envisage a VLAN identifier in that range as an individual instance identifier for one of a maximum of V connections terminating at the given MAC address. The combination of the VLAN identifier and the MAC address is globally unique, with the MAC address identifying the logical administrative owner of a specific VLAN identifier value. A control or management plane can now be used to populate the forwarding tables for the designated VLAN identifier range. To create a unidirectional connection, all that is required is to populate the required VLAN/MAC-tuple into each of the network elements along the path. A mirror image operation can be used to create a path in the opposite direc- tion to create a bidirectional path. This gives us the ability to create engineered paths for the designated VLAN range and Ethernet bridged behavior alongside it for the remaining VLANs. This ability to create traffic-engineered paths is imaginatively called Provider Back- bone Bridging with Traffic Engineering (PBB-TE) and is currently in development in the IEEE The Evolution of Ethernet Network Management Customer Customer Network Network DA BEB1, VLAN ID 89 DA BEB3, VLAN ID 90 Fig. 14.6 Traffic-engineered paths. 802.1 committee in the form of 802.1Qay (IEEE 802.1Qay, in progress). The application of this technique is illustrated in Figure 14.6. In the figure, backbone edge bridges, BEB1 and BEB2, correspond to the edge of the provider backbone bridged network and are 802.1ah-compliant devices that offer customer-facing ports. The backbone edge bridges map the customer traffic onto configured Ethernet Switched Paths (ESPs). In this example backbone VLAN identifiers 89 and 90 are within the range set aside for configured behavior. Two ESPs have been configured from BEB1 to BEB2, and the MAC address of BEB2 