Juniper Networks J-Series Mpls Connection Checking, Options for Checking Mpls Connections, Quit

Chapter 12: Using Services Router Diagnostic Tools

Table 106: CLI Diagnostic Command Summary (continued)

Command	Function
start	Exits the CLI and starts a UNIX shell.
configuration	Enters configuration mode.
	For details, see the Getting Started Guide for your router.
quit	Exits the CLI and returns to the UNIX shell.

MPLS Connection Checking

Use either the J-Web ping MPLS diagnostic tool or the CLI ping mpls command 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 Services Router 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 Services Router receives the response packet, it reports a successful ping response.

Responses that take longer than 2 seconds are identified as failed probes.

Table 107 on page 213 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 107: Options for Checking MPLS Connections

J-Web Ping MPLS	ping mpls Command	Purpose
Tool
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
		Services Router pings a particular LSP
		using the configured LSP name.

Additional Information

When an RSVP-signaled LSP has several paths, the Services Router sends the ping requests on the path that is currently active.

Diagnostic Tools Overview ■ 213