%% You should probably cite draft-ietf-core-groupcomm instead of this I-D.
@techreport{rahman-core-groupcomm-07,
    number =    {draft-rahman-core-groupcomm-07},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-rahman-core-groupcomm/07/},
    author =    {Akbar Rahman and Esko Dijk},
    title =     {{Group Communication for CoAP}},
    pagetotal = 35,
    year =      2011,
    month =     oct,
    day =       12,
    abstract =  {This is a working document intended to trigger discussion and develop draft text for the CoAP protocol specification in the area of group communication. Engineering tradeoffs become more challenging in constrained environments, therefore group communication is considered within the context of adjacent topics that may impact or be impacted by design choices in the subject area. A solution based on IP multicast is proposed.},
}