@techreport{ietf-bliss-problem-statement-04,
    number =    {draft-ietf-bliss-problem-statement-04},
    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-bliss-problem-statement/04/},
    author =    {Jonathan Rosenberg},
    title =     {{Basic Level of Interoperability for Session Initiation Protocol (SIP) Services (BLISS) Problem Statement}},
    pagetotal = 20,
    year =      2009,
    month =     mar,
    day =       9,
    abstract =  {The Session Initiation Protocol (SIP) has been designed as a general purpose protocol for establishing and managing multimedia sessions. It provides many core functions and extensions in support of features such as transferring of calls, parking calls, and so on. However, interoperability of more advanced features between different vendors has been poor. This document describes the reason behind these interoperability problems, and presents a framework for addressing them.},
}