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    trace mpls ip


    trace mpls ip [ vrf vrfName ]
    { targetIpAddress targetIpv4Mask | targetIpv6Prefix }
    [ data-size dataSize ]
    [ destination startIpAddress endIpAddress increment ]
    [ source address sourceAddr ]
    [ ttl ttlValue ] [ timeout timeOutVal ]
    [ reply mode { ipv4-udp | ipv4-udp-with-router-alert } ]
    [ reply pad-tlv ] [ reply dscp trafficClass ]
    [ exp-bits bitValue ] [ detail ]

    Release Information

    Command introduced in JunosE Release 8.0.0.

    data-size keyword and dataSize variable added in JunosE Release 11.1.0.


    Sends MPLS echo request packets with successively higher TTL values to the specified IP or IPv6 address. Discovers the path MPLS packets follow to the destination. There is no no version.

    The MPLS echo request packets and echo reply packets created by this command use the LDP IPv4 sub-TLV described in RFC 4379—Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures (February 2006).


    • vrfName—Name of the VRF context; when you specify a VRF name, the LSP to the specified prefix must originate from the VRF because the ping is generated from the specified VRF
    • targetIpAddress—IP address of the ping target
    • targetIpv4Mask—Network mask for target IP address
    • targetIpv6Prefix—IPv6 address of the ping target
    • dataSize—Size of the LSP ping message (does not include the UDP, IP, and MPLS headers of the packet); in the range 0–6400 bytes. The default value is 100 bytes.
    • startIpAddress—First IP address within the destination range
    • endIpAddress—Last IP address within the destination range
    • increment—Number in the range 0–255 that specifies the increment between addresses in the destination address range
    • sourceAddr—IP address used as the packet source address
    • ttlValue—Hop count specified by setting the time-to-live field in the header, in the range 1–255; default value is 32
    • timeOutVal—Number of seconds in the range 1–32 to wait for an MPLS echo reply packet before the connection attempt times out
    • reply mode—Specifies the reply mode for the echo request packet
      • ipv4-udp—Specifies that the echo request packet is an IPv4 UDP packet
      • ipv4-udp-with-router-alert—Specifies that the echo request packet is an IPv4 UDP packet with the router alert bit set in the header so all routers examine this packet more closely to determine whether further processing is necessary
    • reply pad-tlv—Requests sender of an echo reply to send a pad TLV
    • trafficClass—Number in the range 0–255 that represents the value of the traffic class that the sender of an echo reply is requested to set
    • bitValue—Value of the EXP bits in the range 0–7 included in the MPLS echo request packet
    • detail—Displays detailed information about MPLS echo request sent and echo replies received


    Privileged Exec, User Exec

    Published: 2014-08-18