Help us improve your experience.

Let us know what you think.

Do you have time for a two-minute survey?


Monitoring Network Reachability by Using the MPLS Traceroute Capability


You can perform a traceroute operation to examine the network reachability and identify connection failures from a source or ingress host to a remote host for an MPLS LSP signaled by RSVP. It a debugging tool to locate MPLS label-switched path (LSP) forwarding issues in a network. (Currently supported for IPv4 packets only.)

  1. From the View selector, select Service View.

    The functionalities that you can configure in this view are displayed.

  2. Click the Monitor mode icon in the Service View of the Connectivity Services Director banner.

    The workspaces that are applicable to this mode are displayed.

  3. From the Service View pane, which is the left pane in the window, click the plus sign (+) next to Network Services to expand the tree and display the different service types that you can configure.
  4. Click the plus sign (+) beside Tunnels > LSPs, and select the RSVP service for which you want to run the traceroute utility.
  5. From the task pane, select MPLS Traceroute.

    The MPLS Traceroute Service Type - Service Name window appears.

  6. In the Endpoint Device section, do the following:
    1. From the Ingress Device list, select the ingress device of the LSP, whose IP address to be used as the packet source address. The local router always is considered to be the ingress router, which is the beginning of the LSP. The software automatically determines the proper outgoing interface and IP address to use to reach the next router in an LSP.
    2. From the Egress Device list, select the egress device that is connected using the LSP from the ingress LSP, whose IP address is used of the target for the MPLS traceroute packets.

      The name of the LSP is displayed in the LSP Name field.

  7. On the Advance Options list, do the following:
    1. In the Probe Retries field, specify the number of times to resend probe. The range of values is 1 through 9. The default value is 3.

    2. In the Hop Limit field, specify the maximum number of routers that an LSP can traverse. The configured hop limit includes the ingress and egress routers. You can specify a hop limit for an LSP and for both primary and secondary paths. By default, each LSP can traverse a maximum of 255 hops, including the ingress and egress routers. The number of hops can be from 2 through 255. (A path with two hops consists of the ingress and egress routers only.)

    3. In the Class of Service field, specify the class-of-service (CoS) value given to all packets in the LSP. The CoS value might affect the scheduling or queuing algorithm of traffic traveling along an LSP. A higher value typically corresponds to a higher level of service. The range is from 1 through 7. If you do not specify a CoS value, the IP precedence bits from the packet’s IP header are used as the packet’s CoS value

  8. In the Format list, select XML to display the result or the response of the MPLS traceroute operation in XML format. Alternatively, select ASCII to display the output in the format in which it is displayed on the CLI. The Junos XML API is an XML representation of Junos configuration statements and operational mode commands. Junos XML configuration tag elements are the contents to which the Junos XML protocol operations apply. Junos XML operational tag elements are equivalent in function to operational mode commands in the CLI, which administrators use to retrieve status information for a device.
  9. Click Traceroute to start the traceroute application and to send the MPLS traceroute requests from the source to the destination device.

    The results of the traceroute operation are displayed in the Response Console pane at the bottom of the MPLS Traceroute Service Type - Service Name window.