Source note · Passing call context with SIP UUI and custom headers
In RFC 7433, when the User-to-User 'purpose' parameter is absent the ISDN UUI package (isdn-uui) applies by default.
Checked 2026-10-02
If the 'purpose' header field parameter is not present, the ISDN UUI MUST be used.
- Vendor
- not restricted
- Product
- not restricted
- Subsystem
- SIP User-to-User header
- Deployment
- any
- Region
- not restricted
- Release range
- RFC 7433
- Checked
- 2026-10-02
Sources
- RFC 7433: A Mechanism for Transporting User-to-User Call Control Information in SIP — IETF / RFC Editor · tier 1 standards and regulators · Section 4 (purpose parameter)
Cite this note
APA
WarmTransfer. (2026, October 2). Passing call context with SIP UUI and custom headers: source note sip-uui-context-passing-rfc7433-purpose-default-isdn. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-uui-context-passing-rfc7433-purpose-default-isdn
BibTeX
@misc{warmtransfer-claim-sip-uui-context-passing-rfc7433-purpose-default-isdn,
title = {Passing call context with SIP UUI and custom headers: source note sip-uui-context-passing-rfc7433-purpose-default-isdn},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/sip-uui-context-passing-rfc7433-purpose-default-isdn},
note = {Source note sip-uui-context-passing-rfc7433-purpose-default-isdn, checked 2026-10-02}
}