…P address and port); note that this requires support for the SIP UPDATE method [RFC3311]. Also, to ensure that two media sessions are not inadvertently established prior to the UPDATE being processed by one of them, use security preconditions [sprecon]. Finally, note that all SIP…

… that a renegotiation is initiated using the SIP-REFER [RFC3515] or SIP-UPDATE [RFC3311] methods. It is RECOMMENDED to negotiate the image size during this renegotiation. Johansson & Jung Standards Track [Page 15] RFC 6236 Image Attributes in SDP May 2011 3.2.9. Use with Layered …

…at a renegotiation is initiated using the SIP-REFER [ RFC3515 ] or SIP-UPDATE [ RFC3311 ] methods. It is RECOMMENDED to negotiate the image size during this renegotiation. Johansson & Jung Standards Track [Page 15] RFC 6236 Image Attributes in SDP May 2011 3.2.9 . Use with Layere…