%% You should probably cite draft-ietf-cuss-sip-uui-reqs instead of this I-D.
@techreport{johnston-cuss-sip-uui-reqs-00,
    number =    {draft-johnston-cuss-sip-uui-reqs-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-johnston-cuss-sip-uui-reqs/00/},
    author =    {Alan Johnston and Joanne McMillen and Laura Liess},
    title =     {{Problem Statement and Requirements for Transporting User to User Call Control Information in SIP}},
    pagetotal = 13,
    year =      2010,
    month =     sep,
    day =       15,
    abstract =  {This document introduces the transport of call control related User to User Information (UUI) in the Session Initiation Protocol (SIP), and develops several requirements for a new SIP mechanism. Some SIP sessions are established by or related to a non-SIP application. This application may have information that needs to be transported between the SIP User Agents during session establishment. A common example in another protocol is the ITU-T Q.931 User to User Information Service. As networks move to SIP it is important that applications requiring this data can continue to function in SIP networks as well as the ability to interwork with this ISDN service for end-to-end transparency. This document discusses requirements and approaches. This extension will also be used for native SIP endpoints implementing similar services and interworking with ISDN services. Example use cases include an exchange between two user agents, retargeting by a proxy, and redirection. An example application is an Automatic Call Distributor (ACD) in a contact center.},
}