%% You should probably cite draft-ietf-hip-nat-traversal instead of this I-D.
@techreport{schmitt-hip-nat-traversal-02,
    number =    {draft-schmitt-hip-nat-traversal-02},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-schmitt-hip-nat-traversal/02/},
    author =    {Vivien Schmitt},
    title =     {{HIP Extensions for the Traversal of Network Address Translators}},
    pagetotal = 33,
    year =      2006,
    month =     oct,
    day =       19,
    abstract =  {This document specifies extensions to Host Identity Protocol (HIP) to support traversal of Network Address Translator (NAT) middleboxes. The traversal mechanism tunnels HIP control and data traffic over UDP and enables HIP initiators which MAY be behind NATs to contact HIP responders which MAY be behind another NAT.},
}