Use the ping mpls commands to diagnose the state of LSPs, Layer 2 and Layer 3 VPNs, and Layer 2 circuits. When you issue a command from a Services Router operating as the inbound node at the entry point of an LSP or VPN, the router sends probe packets into the LSP or VPN. Based on how the LSP or VPN outbound node at the remote endpoint of the connection replies to the probes, you can determine the connectivity of the LSP or VPN.
Each probe is an echo request sent to the LSP or VPN exit point as an MPLS packet with a UDP payload. If the outbound node receives the echo request, it checks the contents of the probe and returns a value in the UDP payload of the response packet. If the Services Router receives the response packet, it reports a successful ping response. Responses that take longer than 2 seconds are identified as failed probes.
Alternatively, you can use the J-Web ping MPLS tool. For more information, see Checking MPLS Connections from the J-Web Interface.
Before using ping mpls commands in your network, read Ping MPLS Preparation.
The ping mpls commands diagnose the connectivity of MPLS and VPN networks in the following ways: