Probe and stop probe messages associated with an ingress access point are processed at an egress label switched router. The ingress access point may consist of an identifier of an ingress network element, in combination with a LSP identifier provided by the ingress network element. Auto-registration is performed upon receipt of a probe message indicating an ingress access point not currently being tracked. In the event that a probe message is received indicating an ingress access point not currently being tracked, the egress label switched router adds an entry to a tracking data structure, and a central processor is notified. Each entry within the tracking data structure stores information for a corresponding ingress access point, including knowledge digests from probe messages and an indication of the time a last previous probe message was received. As probe and stop probe messages are received, the knowledge digests they include are compared with the knowledge digests stored in the corresponding tracking table entries. In the event of a conflict between a received knowledge digest and a stored knowledge digest, a predetermined action is taken, such as generation of a misbranching alarm. The knowledge digests may, for example, be Bloom Filters. In the event a stop probe message is received for an ingress access point associated with one of the entries in the tracking table, the corresponding tracking entry is removed.