@misc{rfc3311,
    series =    {Request for Comments},
    number =    3311,
    howpublished =  {RFC 3311},
    publisher = {RFC Editor},
    doi =       {10.17487/RFC3311},
    url =       {https://www.rfc-editor.org/info/rfc3311},
    author =    {Jonathan Rosenberg},
    title =     {{The Session Initiation Protocol (SIP) UPDATE Method}},
    pagetotal = 13,
    year =      2002,
    month =     oct,
    abstract =  {This specification defines the new UPDATE method for the Session Initiation Protocol (SIP). UPDATE allows a client to update parameters of a session (such as the set of media streams and their codecs) but has no impact on the state of a dialog. In that sense, it is like a re-INVITE, but can be sent before the initial INVITE has completed. This makes it very useful for updating session parameters within early dialogs.},
}