When there is a topology change in a sub-ring, the information needs to be propagated over the major ring. This propagation involves the transmission of R-APS (MAC flush event) PDUs over the major ring associated with the sub-ring. This results in a filter database (FDB) flush on the major ring nodes.You can enable this propagation by means of the raps-propagate-tc command on the sub-ring ERP instance.
The following example enables the propagation of topology change information.
device# configure terminal device(config)# erp 1 device(config-erp-1)# raps-propagate-tc