@misc{rfc3603,
    series =    {Request for Comments},
    number =    3603,
    howpublished =  {RFC 3603},
    publisher = {RFC Editor},
    doi =       {10.17487/RFC3603},
    url =       {https://www.rfc-editor.org/info/rfc3603},
    author =    {Bill Marshall and Flemming Andreasen},
    title =     {{Private Session Initiation Protocol (SIP) Proxy-to-Proxy Extensions for Supporting the PacketCable Distributed Call Signaling Architecture}},
    pagetotal = 28,
    year =      2003,
    month =     oct,
    abstract =  {In order to deploy a residential telephone service at very large scale across different domains, it is necessary for trusted elements owned by different service providers to exchange trusted information that conveys customer-specific information and expectations about the parties involved in the call. This document describes private extensions to the Session Initiation Protocol (SIP) (RFC3261) for supporting the exchange of customer information and billing information between trusted entities in the PacketCable Distributed Call Signaling Architecture. These extensions provide mechanisms for access network coordination to prevent theft of service, customer originated trace of harassing calls, support for operator services and emergency services, and support for various other regulatory issues. The use of the extensions is only applicable within closed administrative domains, or among federations of administrative domains with previously agreed-upon policies where coordination of charging and other functions is required.},
}