RFC 7434: Interworking ISDN Call Control User Information with SIP

Publisher

IETF / RFC Editor

URL

https://www.rfc-editor.org/rfc/rfc7434.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

• Because RFC 7433 hex encoding uses two characters per octet, a 128-octet isdn-uui payload plus protocol discriminator takes about 258 hex characters on the wire, so vendor '128 character' limits and RFC '128 octet' limits are not the same budget. inferred in context
• RFC 7434 expects that a limit of 128 octets of UUI data plus the protocol discriminator can be imposed on isdn-uui data. in context
• RFC 7434 restricts the isdn-uui package to the initial INVITE and to BYE within an INVITE dialog; re-INVITEs and other methods are not used for it. in context
• RFC 7434 defines the 'isdn-uui' package for the SIP User-to-User header to interwork with the ISDN User-to-User Signalling service 1 (implicit). in context
• RFC 7434 requires a receiving SIP entity to ignore an isdn-uui User-to-User header whose 'encoding' parameter is present with a value other than 'hex'. in context
• RFC 7434 notes that UUI data exceeding what an ISDN interworking point supports can be discarded there without any error being signalled back to the sender. in context
• RFC 7434 requires the sending application to put a protocol discriminator octet (per ITU-T Q.931) as the first octet of isdn-uui data. in context

Cite this source record

APA

WarmTransfer. (2015, January 1). RFC 7434: Interworking ISDN Call Control User Information with SIP. WarmTransfer. https://warmtransfer.net/knowledge/sources/rfc-7434-isdn-uui-interworking

BibTeX

@misc{warmtransfer-rfc-7434-isdn-uui-interworking,
  title  = {RFC 7434: Interworking ISDN Call Control User Information with SIP},
  author = {{WarmTransfer}},
  year   = {2015},
  url    = {https://warmtransfer.net/knowledge/sources/rfc-7434-isdn-uui-interworking},
  note   = {IETF / RFC Editor, accessed 2026-10-02}
}