Description: A Boolean value set by management. If TRUE causes the Port not to propagate received topology change notifications and topology changes to other Ports. This parameter should be FALSE by default. If set it can cause temporary loss of connectivity after changes in a spanning trees active topology as a result of persistent incorrectly learnt station location information. It is set by a network administrator to prevent bridges external to a core region of the network causing address flushing in that region, possibly because those bridges are not under the full control of the administrator or MAC_Operational for the attached LANs transitions frequently.