Related Documentation
MPLS Connection Checking Overview
Use either the J-Web ping MPLS diagnostic tool or the CLI commands ping mpls, ping mpls l2circuit, ping mpls l2vpn, and ping mpls l3vpn to diagnose the state of label-switched paths (LSPs), Layer 2 and Layer 3 virtual private networks (VPNs), and Layer 2 circuits.
When you use the ping MPLS feature from a J Series device operating as the inbound (ingress) 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 (egress) 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 J Series device receives the response packet, it reports a successful ping response.
Responses that take longer than 2 seconds are identified as failed probes.
Table 1 summarizes the options for using either the J-Web ping MPLS diagnostic tool or the CLI ping mpls command to display information about MPLS connections in VPNs and LSPs.
Table 1: Options for Checking MPLS Connections
J-Web Ping MPLS Tool | ping mpls Command | Purpose | Additional Information |
|---|---|---|---|
Ping RSVP-signaled LSP | ping mpls rsvp | Checks the operability of an LSP that has been set up by the Resource Reservation Protocol (RSVP). The J Series device pings a particular LSP using the configured LSP name. | When an RSVP-signaled LSP has several paths, the J Series device sends the ping requests on the path that is currently active. |
Ping LDP-signaled LSP | ping mpls ldp | Checks the operability of an LSP that has been set up by the Label Distribution Protocol (LDP). The J Series device pings a particular LSP using the forwarding equivalence class (FEC) prefix and length. | When an LDP-signaled LSP has several gateways, the J Series device sends the ping requests through the first gateway. Ping requests sent to LDP-signaled LSPs use only the master routing instance. |
Ping LSP to Layer 3 VPN prefix | ping mpls l3vpn | Checks the operability of the connections related to a Layer 3 VPN. The J Series device tests whether a prefix is present in a provider edge (PE) device’s VPN routing and forwarding (VRF) table, by means of a Layer 3 VPN destination prefix. | The J Series device does not test the connection between a PE device and a customer edge (CE) router. |
Locate LSP using interface name | ping mpls l2vpn interface | Checks the operability of the connections related to a Layer 2 VPN. The J Series device directs outgoing request probes out the specified interface. | – |
Instance to which this connection belongs | ping mpls l2vpn instance | Checks the operability of the connections related to a Layer 2 VPN. The J series device pings on a combination of the Layer 2 VPN routing instance name, the local site identifier, and the remote site identifier, to test the integrity of the Layer 2 VPN circuit (specified by the identifiers) between the inbound and outbound PE routers. | – |
Locate LSP from interface name | ping mpls l2circuit interface | Checks the operability of the Layer 2 circuit connections. The J Series device directs outgoing request probes out the specified interface. | – |
Locate LSP from virtual circuit information | ping mpls l2circuit virtual-circuit | Checks the operability of the Layer 2 circuit connections. The J Series device pings on a combination of the IPv4 prefix and the virtual circuit identifier on the outbound PE router, testing the integrity of the Layer 2 circuit between the inbound and outbound PE routers. | – |
Ping end point of LSP | ping mpls lsp-end-point | Checks the operability of an LSP endpoint. The J Series device pings an LSP endpoint using either an LDP FEC prefix or an RSVP LSP endpoint address. | – |
