Source note · Early media and ringback behavior
RFC 6337 says that once a UAS has sent the answer in a reliable provisional response it should not include SDP in later responses to the INVITE, and a UAC should be ready to receive and ignore such SDP from non-conforming peers.
Checked 2026-09-24
- Vendor
- IETF
- Product
- SIP
- Subsystem
- offer/answer
- Deployment
- any
- Region
- not restricted
- Release range
- RFC 6337
- Checked
- 2026-09-24
Sources
- RFC 6337: Session Initiation Protocol (SIP) Usage of the Offer/Answer Model — IETF / RFC Editor · tier 1 standards and regulators · Section 3.1.1
Cite this note
APA
WarmTransfer. (2026, September 24). Early media and ringback behavior: source note early-media-ringback-no-sdp-repeat-2xx. WarmTransfer. https://warmtransfer.net/knowledge/claims/early-media-ringback-no-sdp-repeat-2xx
BibTeX
@misc{warmtransfer-claim-early-media-ringback-no-sdp-repeat-2xx,
title = {Early media and ringback behavior: source note early-media-ringback-no-sdp-repeat-2xx},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/early-media-ringback-no-sdp-repeat-2xx},
note = {Source note early-media-ringback-no-sdp-repeat-2xx, checked 2026-09-24}
}