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Monitoring Network Reachability by Using the Layer 3 VPN Ping Capability

In IP networks, you can use the ping and traceroute commands to verify network connectivity and find broken links or loops. In an MPLS-enabled network, you can use the mpls ping and trace mpls commands to detect plane failures in different types of MPLS applications and network topologies.

  1. From the View selector, select Service View. The functionalities that you can configure in this view are displayed on the View pane.
  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 on the Tasks pane.
  3. Click the plus sign (+) beside Connectivity to view services based on protocols.
  4. Expand the IP Services tree to select an IP service.
  5. From the Tasks pane, select MPLS Ping.

    The MPLS Ping Service Type - Service Name window appears.

  6. In the Endpoint Device section, do the following:

    The source device sends an MPLS echo request packet to the specified IP or IPv6 address or, alternatively, sends MPLS echo packets to the egress node in a point-to-multipoint LSP. The MPLS echo request packets and echo reply packets created by this command use the LDP IPv4 LSP sub-TLV described in RFC 4379—Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures (February 2006).

    1. From the Source Device list, select the source device, whose IP address is to be used as the packet source address.
    2. From the Destination Device list, select the target endpoint, whose IP address is used as the target IP address for MPLS ping packets or echo requests.
  7. On the Advance Options list, do the following:
    1. In the Ping count (packets) field, enter the number of packets to send to the destination address, in the range 0–4294967295. The default value is 5 and 0 (zero) means ping forever.

    2. In the Ping size (bytes) field, specify the number of bytes comprising the MPLS packet, including the header, in the range 0–64000. The default value is 100 bytes.

    3. In the Forwarding Class field, specify the value of the forwarding class for the MPLS ping packets.

    4. In the Sweep field, configure the payload size, which enables you to vary the sizes of the echo packets being sent. This capability is useful for determining the minimum sizes of the MTUs configured on the nodes along the path to the destination address. This reduces packet fragmentation, which contributes to performance problems. The default is not to sweep; all packets are of the same size.

    5. From the Reply Mode field, select the reply mode for the echo request packet:

      • IP-UDP—Specifies that the echo request packet is an IPv4 UDP packet

      • Application Level Control Channel—Specifies that the echo request packet is replied using the application-level control channel connection.

  8. From the Format list, select XML to display the result or the response of the MPLS ping 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 on the CLI, which administrators use to retrieve status information for a device.
  9. Click Ping to start the ping operation and to send the MPLS echo requests from the source to the destination device.

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