@misc{rfc5443,
    series =    {Request for Comments},
    number =    5443,
    howpublished =  {RFC 5443},
    publisher = {RFC Editor},
    doi =       {10.17487/RFC5443},
    url =       {https://www.rfc-editor.org/info/rfc5443},
    author =    {Markus Jork and Alia Atlas and Luyuan Fang},
    title =     {{LDP IGP Synchronization}},
    pagetotal = 7,
    year =      2009,
    month =     mar,
    abstract =  {In certain networks, there is dependency on the edge-to-edge Label Switched Paths (LSPs) setup by the Label Distribution Protocol (LDP), e.g., networks that are used for Multiprotocol Label Switching (MPLS) Virtual Private Network (VPN) applications. For such applications, it is not possible to rely on Internet Protocol (IP) forwarding if the MPLS LSP is not operating appropriately. Blackholing of labeled traffic can occur in situations where the Interior Gateway Protocol (IGP) is operational on a link on which LDP is not. While the link could still be used for IP forwarding, it is not useful for MPLS forwarding, for example, MPLS VPN applications or Border Gateway Protocol (BGP) route-free cores. This document describes a mechanism to avoid traffic loss due to this condition without introducing any protocol changes. This memo provides information for the Internet community.},
}