Source note · SIP trace capture and ladder analysis
When an INVITE receives a non-2xx final response, the ACK to that response is part of the same INVITE transaction.
Checked 2026-09-23
If the request is INVITE and the final response is a non-2xx, the transaction also includes an ACK to the response.
- Vendor
- IETF
- Product
- SIP
- Subsystem
- transactions
- Deployment
- multi-tenant, on-premises
- Region
- not restricted
- Release range
- RFC 3261 (June 2002)
- Checked
- 2026-09-23
Sources
- RFC 3261 — SIP: Session Initiation Protocol — IETF / RFC Editor · tier 1 standards and regulators · Section 6 Definitions, entry 'Transaction'
Cite this note
APA
WarmTransfer. (2026, September 23). SIP trace capture and ladder analysis: source note sip-trace-analysis-ack-non-2xx-in-txn. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-trace-analysis-ack-non-2xx-in-txn
BibTeX
@misc{warmtransfer-claim-sip-trace-analysis-ack-non-2xx-in-txn,
title = {SIP trace capture and ladder analysis: source note sip-trace-analysis-ack-non-2xx-in-txn},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/sip-trace-analysis-ack-non-2xx-in-txn},
note = {Source note sip-trace-analysis-ack-non-2xx-in-txn, checked 2026-09-23}
}