Reverse Notification Tree For Data Networks

Abstract

Recovery time upon the failure of a link or switching system in an asynchronous data network can be minimized if downstream data switches provide upstream messages indicating to an upstream switching system that the downstream traffic arrived intact and was properly handled. Upon this loss or failure of the upstream status message to an upstream switching system, an upstream switching system can reroute data traffic around a failed link or failed switch with a minimal amount of lost data. The upstream status message is conveyed from a downstream switching system to an upstream switching system via a reverse notification tree data pathway.

What is claimed is: 
     
         1 . A network node for managing data within a multi-protocol label switching (MPLS) network, the network node comprising:
 a transmitter module configured to transmit downstream data to a downstream switching system or to an upstream switching system, or retransmit downstream data received from an upstream switching system to the downstream switching system; and   a reverse path notification module configured to retransmit an upstream reverse path notification message received from the downstream switching system to the upstream switching system or to generate and transmit an upstream reverse path notification message to the upstream switching system;   the network node being either between or the same as the downstream switching system or the upstream switching system.   
     
     
         2 . The network node of  claim 1 , wherein the network node transmits or retransmits through a different medium from which it receives. 
     
     
         3 . The network node of  claim 1 , wherein the network node is between the downstream switching system and the upstream switching system and the reverse path notification module is further configured to provide a fault status indication to the upstream switching system, the fault status indication indicating to the upstream switching system that a fault has occurred in the downstream switching system or the network node. 
     
     
         4 . The network node of  claim 3 , wherein the reverse path notification module is configured to provide the fault status indication through the upstream reverse path notification message. 
     
     
         5 . The network node of  claim 3 , wherein the network node is between the downstream switching system and the upstream switching system and the fault status indication indicates to the upstream switching system to re-route downstream data destined for the downstream switching system through another network node, the another network node being separate from the network node. 
     
     
         6 . The network node of  claim 1 , wherein the network node maintains a table identifying other upstream switching systems including the upstream switching system. 
     
     
         7 . The network node of  claim 1 , wherein the network node is between the downstream switching system and the upstream switching system and the transmitter module is further configured to transmit or retransmit downstream data from the upstream switching system to the downstream switching system, the downstream data originally destined to be transmitted through a different network node from the network node, the downstream data being re-routed through the network node due to a fault indication received by the upstream switching system from the different network node. 
     
     
         8 . The network node of  claim 1 , wherein the network node is between the downstream switching system and the upstream switching system and the reverse path notification module further configured to provide a fault status indication in the upstream reverse path notification message to the upstream switching system, the fault status indication indicating to the upstream switching system that a fault has occurred in the downstream switching system or the network node. 
     
     
         9 . The network node of  claim 1 , wherein the network node is between the downstream switching system and the upstream switching system and the network node is configured to generate an error message to the upstream switching system in response to receiving an indication from the downstream switching system that a fault has occurred in the downstream switching system. 
     
     
         10 . The network node of  claim 9 , wherein the reverse path notification module is further configured to transmit the error message to the upstream switching system. 
     
     
         11 . The network node of  claim 9 , wherein the error message instructs the upstream switching system to re-route downstream data destined for the downstream switching system through another network node, the another network node separate from the network node. 
     
     
         12 . A method for managing data within a multi-protocol label switching (MPLS) network at a network node, the method comprising:
 transmitting downstream data to a downstream switching system or to an upstream switching system, or retransmitting downstream data received from an upstream switching system to the downstream switching system; and   retransmitting an upstream reverse path notification message received from the downstream switching system to the upstream switching system or generating and transmitting an upstream reverse path notification message to the upstream switching system;   the network node being either between or the same as the downstream switching system or the upstream switching system.   
     
     
         13 . The method of  claim 12 , wherein transmitting or retransmitting occurs through a different medium from receiving. 
     
     
         14 . The method of  claim 12 , wherein the network node is between the downstream switching system and the upstream switching system, the method further comprising providing a fault status indication to the upstream switching system, the fault status indication indicating to the upstream switching system that a fault has occurred in the downstream switching system or the network node. 
     
     
         15 . The method of  claim 14 , the method further comprising providing the fault status indication through the upstream reverse path notification message. 
     
     
         16 . The method of  claim 14 , wherein the network node is between the downstream switching system and the upstream switching system, the fault status indication indicating to the upstream switching system to re-route downstream data destined for the downstream switching system through another network node, the another network node being separate from the network node. 
     
     
         17 . The method of  claim 12 , wherein maintaining a table identifying other upstream switching systems includes maintaining information about the upstream switching system. 
     
     
         18 . The method of  claim 12 , wherein the network node is between the downstream switching system and the upstream switching system, the method further comprising transmitting or retransmitting downstream data from the upstream switching system to the downstream switching system, the downstream data originally destined to be transmitted through a different network node from the network node, the downstream data being re-routed through the network node due to a fault indication received by the upstream switching system from the different network node. 
     
     
         19 . The method of  claim 12 , wherein the network node is between the downstream switching system and the upstream switching system, the method further comprising providing a fault status indication in the upstream reverse path notification message to the upstream switching system, the fault status indication indicating to the upstream switching system that a fault has occurred in the downstream switching system or the network node. 
     
     
         20 . The method of  claim 12 , wherein the network node is between the downstream switching system and the upstream switching system, the method further comprising generating an error message to the upstream switching system in response to receiving an indication from the downstream switching system that a fault has occurred in the downstream switching system. 
     
     
         21 . A non-transitory computer readable medium having stored thereon a sequence of instructions which, when loaded and executed by a processor coupled to an apparatus, causes the apparatus to:
 transmit downstream data to a downstream switching system or to an upstream switching system, or retransmit downstream data received from an upstream switching system to the downstream switching system; and   retransmit an upstream reverse path notification message received from the downstream switching system to the upstream switching system or generate and transmit an upstream reverse path notification message to the upstream switching system;   the network node being either between or the same as the downstream switching system or the upstream switching system.