%% You should probably cite draft-hilt-soc-overload-design instead of this I-D.
@techreport{ietf-sipping-overload-design-02,
    number =    {draft-ietf-sipping-overload-design-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-ietf-sipping-overload-design/02/},
    author =    {Volker Hilt and Eric Noel and Charles Shen and Ahmed Abdelal},
    title =     {{Design Considerations for Session Initiation Protocol (SIP) Overload Control}},
    pagetotal = 21,
    year =      2009,
    month =     jul,
    day =       11,
    abstract =  {Overload occurs in Session Initiation Protocol (SIP) networks when SIP servers have insufficient resources to handle all SIP messages they receive. Even though the SIP protocol provides a limited overload control mechanism through its 503 (Service Unavailable) response code, SIP servers are still vulnerable to overload. This document discusses models and design considerations for a SIP overload control mechanism.},
}