Alcatel-Lucent 7210 SAS M Service Manual page 277

Virtual Private LAN Services
be re-learned by all PEs in the VPLS. It is possible to configure two management VPLS services,
where both VPLS services have different active spokes (this is achieved by changing the path-cost
in STP). By associating different user VPLSes with the two management VPLS services, load
balancing across the spokes can be achieved.
In this configuration the scope of STP domain is limited to MTU and PEs, while any topology
change needs to be propagated in the whole VPLS domain.
This is done by using "MAC-flush" messages defined by RFC 4762, Virtual Private LAN Services
Using LDP Signaling. In the case where STP acts as a loop resolution mechanism, every Topology
Change Notification (TCN) received in a context of STP instance is translated into an LDP-MAC
address withdrawal message (also referred to as a MAC-flush message) requesting to clear all
FDB entries except the ones learned from the originating PE. Such messages are sent to all PE
peers connected through SDPs (mesh and spoke) in the context of VPLS service(s) which are
managed by the given STP instance.
7210 SAS M Services Guide Page 277