Source note · Calls that drop after about 30 seconds
The INVITE client transaction must not generate the ACK for a 2xx response; the UAC core sends that ACK in a new transaction.
Checked 2026-09-25
A UAC core will send an ACK to the 2xx response using a new transaction.
- Vendor
- IETF
- Product
- SIP
- Subsystem
- INVITE client 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 17.1.1.2 (Formal Description)
Cite this note
APA
WarmTransfer. (2026, September 25). Calls that drop after about 30 seconds: source note sip-calls-drop-30-seconds-ack-new-transaction. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-calls-drop-30-seconds-ack-new-transaction
BibTeX
@misc{warmtransfer-claim-sip-calls-drop-30-seconds-ack-new-transaction,
title = {Calls that drop after about 30 seconds: source note sip-calls-drop-30-seconds-ack-new-transaction},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/sip-calls-drop-30-seconds-ack-new-transaction},
note = {Source note sip-calls-drop-30-seconds-ack-new-transaction, checked 2026-09-25}
}