Patent ID: 7983174
Filing Date: 2011-07-19
Classification: H04L

Abstract:
1. A method of diagnosing a fault in a Multi Protocol Label Switching (MPLS) network path comprising the steps, performed at a diagnosing node, of: initiating a path discovery test to a destination node; receiving at least one path discovery test response; identifying a diagnosable node on the MPLS network path from the path discovery test response; remotely accessing said diagnosable node; and performing a diagnostic routine, using a layer two service of the Open System Interconnection (OSI) reference model, at said diagnosable node to at least determine whether an MPLS packet handled by said diagnosable node carried an incorrect header; wherein the layer two service does not have information about an exchange of layer three routing information with a service provider; in response to the diagnostic routine not diagnosing the fault at the diagnosable node, using the layer two service of the OSI reference model, the diagnosable node, from forwarding information at the diagnosable node, without sending a test packet, identifying a next-hop node along the MPLS network path to the destination node, and using the layer two service of the OSI reference model, remotely accessing the next-hop node along the MPLS network path to the destination node as a new diagnosable node and performing the diagnostic routine at said new diagnosable node; wherein the method is performed by one or more computing devices; wherein the method is performed in a-the layer two service of the OSI reference model.