Defect detection in ip/mpls network tunnels

Abstract

This disclosure addresses improving the reliability of network connections between nodes, detection of failures of network connections, and the reduction of control packets exchanged between nodes. A second node may stop sending control packets to a first node causing a reduction in network throughput and increased network capacity. The network connection from the first node to the second may be of a first type and the connection from the second node to the first node may be of a second type. When a failure of the connection of the first type occurs, communication of the failure may be sent in a flag from the second node to the first node using the second type. A response to the flag received at the first node may be sent to the second node. The response may be sent using the second type of network connection because the first type failed.

What is claimed is: 
     
         1 . A first network apparatus, comprising:
 a transceiver at the first network apparatus coupled via a network to another transceiver at a second network apparatus, the first network apparatus configured to at least:
 send a message to the second network apparatus to cause a bootstrapping of an asynchronous session with the second network apparatus, wherein the first network apparatus periodically sends first control packets to the second network apparatus via a first network connection and periodically receive from the second network apparatus second control packets via a second network connection; 
 send, to the second network apparatus, in response to changing at the first network apparatus from the asynchronous session to a demand session, a third control packet via the first network connection to cause the second network apparatus to stop sending the second control packets to the first network apparatus; 
 receive, in a fourth control packet from the second network apparatus, a first flag via the second network connection indicating that the demand session from the first network apparatus to the second network apparatus has failed; 
 send, by the first network apparatus, a fifth control packet with a second flag via a third network connection to cause the second network apparatus to stop sending the fourth control packet with the first flag; and 
 send, after sending the fifth packet, to the second network apparatus, a sixth control packet to restart the asynchronous session via the first network connection.