@misc{rfc6337,
    series =    {Request for Comments},
    number =    6337,
    howpublished =  {RFC 6337},
    publisher = {RFC Editor},
    doi =       {10.17487/RFC6337},
    url =       {https://www.rfc-editor.org/info/rfc6337},
    author =    {Shinji OKUMURA and Takuya Sawada and Paul Kyzivat},
    title =     {{Session Initiation Protocol (SIP) Usage of the Offer/Answer Model}},
    pagetotal = 33,
    year =      2011,
    month =     aug,
    abstract =  {The Session Initiation Protocol (SIP) utilizes the offer/answer model to establish and update multimedia sessions using the Session Description Protocol (SDP). The description of the offer/answer model in SIP is dispersed across multiple RFCs. This document summarizes all the current usages of the offer/answer model in SIP communication. This document is not an Internet Standards Track specification; it is published for informational purposes.},
}