Source note · Calls that drop after about 30 seconds
After RFC 6026, retransmissions of a 2xx response to INVITE are handled by the transaction user (the UAS core), not by the INVITE server transaction.
Checked 2026-09-25
It is not retransmitted by the server transaction; retransmissions of 2xx responses are handled by the TU.
- Vendor
- IETF
- Product
- SIP
- Subsystem
- INVITE server transaction
- Deployment
- any
- Region
- not restricted
- Release range
- RFC 6026 and later
- Checked
- 2026-09-25
Sources
- RFC 6026: Correct Transaction Handling for 2xx Responses to Session Initiation Protocol (SIP) INVITE Requests — IETF / RFC Editor · tier 1 standards and regulators · Change to RFC 3261 section 17.2.1 (INVITE Server Transaction)
Cite this note
APA
WarmTransfer. (2026, September 25). Calls that drop after about 30 seconds: source note sip-calls-drop-30-seconds-2xx-retransmit-by-tu. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-calls-drop-30-seconds-2xx-retransmit-by-tu
BibTeX
@misc{warmtransfer-claim-sip-calls-drop-30-seconds-2xx-retransmit-by-tu,
title = {Calls that drop after about 30 seconds: source note sip-calls-drop-30-seconds-2xx-retransmit-by-tu},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/sip-calls-drop-30-seconds-2xx-retransmit-by-tu},
note = {Source note sip-calls-drop-30-seconds-2xx-retransmit-by-tu, checked 2026-09-25}
}