MPLS LSP ping is the name for an MPLS echo request and MPLS echo reply. Ping is a well-known troubleshooting tool for IP networks that is used to figure out if the object is there. If it is, you see an echo. It is like using SONAR on a submarine. Ping uses ICMP, which was designed to augment the IP protocol because it can signal error conditions (destination unreachable, time exceeded, and so on) and send informational advertisements (redirect, address mask, and so on). Ping uses ICMP to carry echo request and echo reply packets. The echo request packet is sent toward the destination, which should then reply with an echo reply packet. The source receiving the echo reply indicates that the two hosts can see each other on the network ...

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