Method of monitoring a tandem connection in a multi-protocol label switching (MPLS) telecommunication network
View Patent ↗It is disclosed a method of monitoring, a Multi-Protocol Label Switching network, a tandem connection of a Label Switched Path. The tandem connection to be monitored has an input node and an output node. The method comprises the following steps: receiving a first Operation Administration Management packet at the input node; and generating a second OAM packet at the input node. According to the invention, the following steps are further performed: a tandem connection header is inserted into the first OAM packet; both the first OAM packet with the tandem connection header and the second OAM packet are sent towards the output node; and the second OAM packet is identified according to the presence or absence of said tandem connection header.
1. A method of monitoring, in a Multi-Protocol Label Switching network, both a label-switched path and a tandem connection that is part of the label-switched path, the tandem connection comprising a sequence of successive nodes, a first of which is an input node and a last of which is an output node, the method comprising:
receiving a first packet at the input node, the first packet having a first switching header;
processing at the input node the first packet to generate a modified version of the first packet that includes within the first packet a recalculated first switching header and a tandem connection header;
generating at the input node a second packet having a second switching header, wherein the second packet is a duplicate version of the first packet that includes within the second packet the recalculated first switching header;
sending towards the output node both the first packet and the second packet;
at the output node, identifying the second packet, and not forwarding the second packet further on the label-switched path; and
at the output node, removing the tandem connection header from the first packet.
2. The method of claim 1 , wherein the first packet is one of a first user packet and a first Operation, Administration and Management (OAM) packet having a first OAM header.
3. The method of claim 1 , wherein the method further comprises the step of identifying a received packet at the output node as being the second packet based on the absence of the tandem connection header.
4. The method of claim 1 , wherein the method further comprises the step of identifying a received packet at the output node as being the first packet based on the presence of the tandem connection header.
5. The method of claim 1 , wherein the first packet is identified for use in monitoring the label-switched path.
6. The method of claim 1 , wherein one or more of the first switching header and the second switching header comprises a label field carrying a label respectively calculated to be processed by the next node receiving the packet.
7. The method of claim 1 , wherein one or more of the first switching header and the second switching header is re-calculated at each intermediate network node to insert a new label adapted to be processed by the next node along the label-switched path.
8. The method of claim 1 , further comprising the step of:
inserting the tandem connection header into the first packet.
9. The method of claim 8 , further comprising the step of:
removing the tandem connection header from the packet.
10. The method of claim 1 , wherein the label-switched path and the tandem connection are monitored substantially concurrently.