%% You should probably cite draft-ietf-l2tpext-keyed-ipv6-tunnel instead of this I-D.
@techreport{mkonstan-l2tpext-keyed-ipv6-tunnel-00,
    number =    {draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-mkonstan-l2tpext-keyed-ipv6-tunnel/00/},
    author =    {Maciek Konstantynowicz and Giles Heron and Rainer Schatzmayr and Wim Henderickx},
    title =     {{Keyed IPv6 Tunnel}},
    pagetotal = 10,
    year =      2013,
    month =     nov,
    day =       5,
    abstract =  {This document describes a simple L2 Ethernet over IPv6 tunnel encapsulation with mandatory 64-bit key for connecting L2 Ethernet attachment circuits identified by IPv6 addresses. The encapsulation is based on L2TPv3 over IP.},
}