Patent ID: 8611353

Claim:
A method for failure localization in an MPLS-TP network comprising a plurality of interconnected routers configured for MPLS-TP, wherein at least a first router is defined as an originating Maintenance End Point, MEP, and a second router is defined as a targeting MEP such that OAM packets are sent from the originating MEP towards the targeting MEP, the method comprises the steps of: associating a table with each MEP, wherein the table comprises information related to the MEPs of the MPLS-TP network, issuing OAM packets from the originating MEP towards the targeting MEP, inserting information from the table associated with router issuing the OAM packets into the issued OAM packets to enable identification of a subsequent MEP or Maintenance Intermediate Point, MIP, upon reception of an OAM packet, issuing a reply packet at the receiving router towards the originating MEP, and inserting into the reply packet information from the table associated with the router issuing the reply packet such that the originating MEP can analyze the reply packet for failure localization, wherein the table comprises at least an identity of a label switch path from the originating MEP towards the targeting MEP, an identity of a label switch path from the targeting MEP towards the originating MEP, a number of hops to a subsequent Maintenance Intermediate Point, MIP, or MEP and a number of hops to the originating MEP, an identity of the originating MEP, an ME identity to which the MEPs and/or MIPs belong, and an identity of the MEP/MIP with which the table is associated, at least a third router is defined as a MIP, and the method further comprises: sending an OAM packet from the originating MEP via the at least one MIP towards the targeting MEP, wherein the OAM packet comprises the identity of the label switched path towards the targeting MEP and, based on information from the table associated with the originating MEP, the number of hops to the subsequent MIP or MEP, and an identity of the originating MEP, wherein at each MIP or MEP receiving said OAM packet the following steps are performed: generating a reply packet towards the originating MEP, and inserting the identity of the label switched path towards the originating MEP, based on information from the table associated with the first MIP, inserting the number of hops to the originating MEP into the reply packet, the identity of said first MIP in said reply packet and the identity of the originating MEP, and at each MIP the further steps are performed: forwarding said OAM packet towards the targeting MEP, and updating the number of hops to the subsequent MIP or MEP based on information from the table, and determining the location of a failure by analyzing the identity of the MIP/MEP of the reply packets at the originating MEP.