RFC 7433: A Mechanism for Transporting User-to-User Call Control Information in SIP

Publisher

IETF / RFC Editor

URL

https://www.rfc-editor.org/rfc/rfc7433.html

Published

2015-01-01

Updated

unknown

Accessed

2026-10-02

HTTP status

200

License

IETF Trust Legal Provisions; IETF text may be quoted with attribution; short excerpts and locators only

Source notes citing this source

• RFC 7433 states that carrying UUI data elements of at least 129 octets in the User-to-User header field is trivial, satisfying its size requirement REQ-11. in context
• RFC 7433 (January 2015, Standards Track) defines the SIP User-to-User header field as a mechanism for transporting user-to-user call control information between the application initiating a session and the application accepting it. in context
• RFC 7433 defines only one value for the User-to-User 'encoding' parameter, 'hex'; other encodings are left to future packages. in context
• RFC 7433 requires user agents to ignore UUI data from packages or encodings they do not understand. in context
• Under RFC 7433 the User-to-User header field may appear in INVITE and BYE requests and in end-to-end responses to them (1xx other than 100, 2xx and 3xx). in context
• RFC 7433 allows a sender to include multiple User-to-User header fields in one message and requires receivers to be prepared to receive multiple. in context
• In RFC 7433, when the User-to-User 'purpose' parameter is absent the ISDN UUI package (isdn-uui) applies by default. in context
• RFC 7433 registers the SIP option tag 'uui' to indicate that a user agent supports and understands the User-to-User header field. in context

Cite this source record

APA

WarmTransfer. (2015, January 1). RFC 7433: A Mechanism for Transporting User-to-User Call Control Information in SIP. WarmTransfer. https://warmtransfer.net/knowledge/sources/rfc-7433-sip-uui-header

BibTeX

@misc{warmtransfer-rfc-7433-sip-uui-header,
  title  = {RFC 7433: A Mechanism for Transporting User-to-User Call Control Information in SIP},
  author = {{WarmTransfer}},
  year   = {2015},
  url    = {https://warmtransfer.net/knowledge/sources/rfc-7433-sip-uui-header},
  note   = {IETF / RFC Editor, accessed 2026-10-02}
}